**2. Cottonseeds**

There are five commercially grown species of cotton:


Oilseed Pests 121

leaves causing bronzing, reddening and sometimes desiccation of the leaf. The crop enjoys warm and dry climates which is appropriate for the mites. Yield loss of the mites depends on when mite populations begin to increase and how quickly they increase (Bailey, 2007).

**Monitoring:** monitor the oldest leaf when plants are very young. As plants grow, choose leaves that are from 3, 4 or 5 nodes below the plant terminal. Begin monitoring at seedling emergence and sample at least weekly. Sample more frequently if the weather conditions are hot and dry. Also, shake the leaves onto a white piece of paper and count the actual number of mites moving around with a hand lens**.** Eggs and immature stages are difficult to

**Economic and action thresholds:** threshold is when 30% of plants infested through the bulk

**Control**: biological control by ladybirds (*Hippodamia convergens* Guerin), big eyed bugs (*Geocoris* spp.), damsel bugs (*Nabis* spp.), lacewings (*Chrysopa* and *Micromus* spp.) and *Phytoseiulus persimilis* (Athias-Henriot) can decrease the population of the mites in early season. Chemical control can be effective by rotation of some acaricides, but only applied when action threshold is observed. Rotation of pesticides is essential because if the same pesticide is used over a prolong period of time they quickly resist to pesticide (Bailey, 2007).

**Identification:** *T. tabaci* adult is about 1 mm long; yellowish-gray to dark-gray and the head has post ocular setae of about the same length as the interocellar setae. The basal segments of the usually seven-segmented antennae are light brown, while the distal segments are dark brown. The prothorax has only two pairs of well developed setae on the posterior margin. The second segment of thoracic has convergent striations on the top surface, and lacks campaniform sensillae. Eggs are microscopic, white or yellow. The nymph ranging from 0.5 to 1.2 mm, white to pale yellow and look like to the adult; just it has short antennas and does not have wings. Pupae are pale yellow to brown, they have short antennae and the

*T. palmi* adults are about 0.8 to 1 mm in length, pale yellow or whitish in color, but with numerous dark setae on the body. A black line, resulting from the juncture of the wings, runs along the back of the body. The slender fringed wings are pale. The hairs or fringe on the anterior edge of the wing are considerably shorter than those on the posterior edge. The egg is colorless to pale white in color and bean-shaped in form. The nymph resembles the adults in general body form though they lack wings and are smaller. The pre pupae and pupae resemble the adults and nymph in form, except that they possess wing pads. The

*S. dorsalis* has small size less than 1 mm in length, yellow coloration, dark antennae with forked sense cones on antennal segments III and IV, antennomeres I-II are pale and III to IX are dark. Also, it has dark striping on the lower abdomen and three distal setae on the lateral margins of abdominal tergites, with pronotal posteromarginal seta II nearly one and a half times the length of I or III, a complete posteromarginal comb on tergite VII; and three

wing pads of the pupae are longer than that of the pre pupae (Capinera, 2010b).

see with the naked eye, so a hand lens should be used (Yvette & Jensen, 2009).

**2.3** *Thrips tabaci* **(Lind.),** *T. palmi* **(Karny) and** *Scirtothrips dorsalis* **(Hood)**

of the season (squaring to first open boll) (Yvette & Jensen, 2009).

wing buds are visible but short and not functional (Rueda, 1995).

ocellar setae with III between posterior ocelli (Wikipedia, 2011d).

**(Thysanoptera: Thripidae)** 

Some of the important pests on cottonseed that require management for realizing better yields are:

#### **2.1 Locusts and grasshoppers**

**Identification:** there are different species of locusts and grasshoppers that attack oilseed crops especially cotton. Australian plague locust, *Chortoicetes terminifera* (Walker), will not generally damage cotton, although some light damage has been observed on field margins as swarms move through and 'test feed'. The spur-throated locust, *Austracris guttulosa* (Walker), if present in large swarms, can cause damage (Bailey, 2007). The variegated grasshopper, *Zonocerus variegatus* (L.) is the only grasshopper pest in the humid forest zone. It causes damage on most crops, mainly cassava, but also cotton (De Groote, 1997).

**Life cycle and damage:** Grasshoppers can be occasional early season pests. In late summer and fall, females lay eggs in grassy foothills, on ditch banks, along roadsides and fence rows, in pasture areas. The eggs hatch in spring and the young nymphs feed on nearby plants. Higher temperatures result in faster development of the eggs and nymphal growth. Hot and dry weather conditions favor population increase, while cool and moist conditions decrease population growth. When wild grasses and other plants become dry, the grasshoppers migrate to irrigated croplands. Both nymphs and adults can defoliate crops or chew through the stem weakening the plant which often will fall over at the wound site. They overwinter in egg cases which were deposited in the soil (Collins et al., 2010).

**Monitoring:** when population densities are high, pest managers can use four 180-degree sweeps with a 15-inch sweep net, which is equivalent to the number of adult (or nymph) grasshoppers per square yard (Knodel et al., 2010).

**Economic and action thresholds:** action threshold is when 8 or more grasshoppers per square yard occur in the field (Knodel et al., 2010).

**Control**: Control of annual weeds before grasshopper emergence may reduce grasshopper populations by eliminating alternative food sources for young grasshoppers. *Beauveria bassiana* (Bals.) and *Metarhizium anisopliae* (pathogenic fungi) can be applied for controlling grasshopper population. Scelionid egg parasites and blister beetle are effective biocontrol agents. If the threshold is exceeded apply some insecticides such as acephate at 0.33 - 0.66 lbs, beta-cyfluthrin at 2.4-3.2 fl oz, bifenthrin at 1.6-6.4 fl oz,and esfenvalerate at low rate of 3.9-5.8 fl oz (Knodel et al., 2010).

#### **2.2** *Tetranychus urticae* **(Koch) (Acari: Tetranychidae)**

**Identification:** the size of the mite is less than 1 mm and varies in the color. The adults have two typical dark spots on the back so they are named two spotted mite. The female is 0.5 mm long; the male is smaller and slender and they have 4 pairs of legs. The females lay small (less than 0.1 mm in diameter) spherical eggs which are translucent after laying. Larva of reduced size has 3 pairs of legs. The common name, red spider mite, is because they spin silk webs to protect the eggs or colony from predators (Bailey, 2007).

**Life cycle and damage**: the eggs hatch into the nymph named protonymph, and then turns into deutonymph, afterward adult stage form. *T. urticae* has worldwide distribution and infests to a wide range of plants. The mites convene and feed on the under surface of the

Some of the important pests on cottonseed that require management for realizing better

**Identification:** there are different species of locusts and grasshoppers that attack oilseed crops especially cotton. Australian plague locust, *Chortoicetes terminifera* (Walker), will not generally damage cotton, although some light damage has been observed on field margins as swarms move through and 'test feed'. The spur-throated locust, *Austracris guttulosa* (Walker), if present in large swarms, can cause damage (Bailey, 2007). The variegated grasshopper, *Zonocerus variegatus* (L.) is the only grasshopper pest in the humid forest zone.

**Life cycle and damage:** Grasshoppers can be occasional early season pests. In late summer and fall, females lay eggs in grassy foothills, on ditch banks, along roadsides and fence rows, in pasture areas. The eggs hatch in spring and the young nymphs feed on nearby plants. Higher temperatures result in faster development of the eggs and nymphal growth. Hot and dry weather conditions favor population increase, while cool and moist conditions decrease population growth. When wild grasses and other plants become dry, the grasshoppers migrate to irrigated croplands. Both nymphs and adults can defoliate crops or chew through the stem weakening the plant which often will fall over at the wound site. They overwinter

**Monitoring:** when population densities are high, pest managers can use four 180-degree sweeps with a 15-inch sweep net, which is equivalent to the number of adult (or nymph)

**Economic and action thresholds:** action threshold is when 8 or more grasshoppers per

**Control**: Control of annual weeds before grasshopper emergence may reduce grasshopper populations by eliminating alternative food sources for young grasshoppers. *Beauveria bassiana* (Bals.) and *Metarhizium anisopliae* (pathogenic fungi) can be applied for controlling grasshopper population. Scelionid egg parasites and blister beetle are effective biocontrol agents. If the threshold is exceeded apply some insecticides such as acephate at 0.33 - 0.66 lbs, beta-cyfluthrin at 2.4-3.2 fl oz, bifenthrin at 1.6-6.4 fl oz,and esfenvalerate at low rate of

**Identification:** the size of the mite is less than 1 mm and varies in the color. The adults have two typical dark spots on the back so they are named two spotted mite. The female is 0.5 mm long; the male is smaller and slender and they have 4 pairs of legs. The females lay small (less than 0.1 mm in diameter) spherical eggs which are translucent after laying. Larva of reduced size has 3 pairs of legs. The common name, red spider mite, is because they spin

**Life cycle and damage**: the eggs hatch into the nymph named protonymph, and then turns into deutonymph, afterward adult stage form. *T. urticae* has worldwide distribution and infests to a wide range of plants. The mites convene and feed on the under surface of the

It causes damage on most crops, mainly cassava, but also cotton (De Groote, 1997).

in egg cases which were deposited in the soil (Collins et al., 2010).

grasshoppers per square yard (Knodel et al., 2010).

square yard occur in the field (Knodel et al., 2010).

**2.2** *Tetranychus urticae* **(Koch) (Acari: Tetranychidae)** 

silk webs to protect the eggs or colony from predators (Bailey, 2007).

3.9-5.8 fl oz (Knodel et al., 2010).

yields are:

**2.1 Locusts and grasshoppers** 

leaves causing bronzing, reddening and sometimes desiccation of the leaf. The crop enjoys warm and dry climates which is appropriate for the mites. Yield loss of the mites depends on when mite populations begin to increase and how quickly they increase (Bailey, 2007).

**Monitoring:** monitor the oldest leaf when plants are very young. As plants grow, choose leaves that are from 3, 4 or 5 nodes below the plant terminal. Begin monitoring at seedling emergence and sample at least weekly. Sample more frequently if the weather conditions are hot and dry. Also, shake the leaves onto a white piece of paper and count the actual number of mites moving around with a hand lens**.** Eggs and immature stages are difficult to see with the naked eye, so a hand lens should be used (Yvette & Jensen, 2009).

**Economic and action thresholds:** threshold is when 30% of plants infested through the bulk of the season (squaring to first open boll) (Yvette & Jensen, 2009).

**Control**: biological control by ladybirds (*Hippodamia convergens* Guerin), big eyed bugs (*Geocoris* spp.), damsel bugs (*Nabis* spp.), lacewings (*Chrysopa* and *Micromus* spp.) and *Phytoseiulus persimilis* (Athias-Henriot) can decrease the population of the mites in early season. Chemical control can be effective by rotation of some acaricides, but only applied when action threshold is observed. Rotation of pesticides is essential because if the same pesticide is used over a prolong period of time they quickly resist to pesticide (Bailey, 2007).

#### **2.3** *Thrips tabaci* **(Lind.),** *T. palmi* **(Karny) and** *Scirtothrips dorsalis* **(Hood) (Thysanoptera: Thripidae)**

**Identification:** *T. tabaci* adult is about 1 mm long; yellowish-gray to dark-gray and the head has post ocular setae of about the same length as the interocellar setae. The basal segments of the usually seven-segmented antennae are light brown, while the distal segments are dark brown. The prothorax has only two pairs of well developed setae on the posterior margin. The second segment of thoracic has convergent striations on the top surface, and lacks campaniform sensillae. Eggs are microscopic, white or yellow. The nymph ranging from 0.5 to 1.2 mm, white to pale yellow and look like to the adult; just it has short antennas and does not have wings. Pupae are pale yellow to brown, they have short antennae and the wing buds are visible but short and not functional (Rueda, 1995).

*T. palmi* adults are about 0.8 to 1 mm in length, pale yellow or whitish in color, but with numerous dark setae on the body. A black line, resulting from the juncture of the wings, runs along the back of the body. The slender fringed wings are pale. The hairs or fringe on the anterior edge of the wing are considerably shorter than those on the posterior edge. The egg is colorless to pale white in color and bean-shaped in form. The nymph resembles the adults in general body form though they lack wings and are smaller. The pre pupae and pupae resemble the adults and nymph in form, except that they possess wing pads. The wing pads of the pupae are longer than that of the pre pupae (Capinera, 2010b).

*S. dorsalis* has small size less than 1 mm in length, yellow coloration, dark antennae with forked sense cones on antennal segments III and IV, antennomeres I-II are pale and III to IX are dark. Also, it has dark striping on the lower abdomen and three distal setae on the lateral margins of abdominal tergites, with pronotal posteromarginal seta II nearly one and a half times the length of I or III, a complete posteromarginal comb on tergite VII; and three ocellar setae with III between posterior ocelli (Wikipedia, 2011d).

Oilseed Pests 123

**Economic and action thresholds:** The economic threshold level in the first open boll stage until harvest is the time if 50% of the plants (counted randomly) are affected or 10% trace

**Control:** planting resistant or tolerant varieties which are densely hairy and with stiff leaves are reliable control technique. Seed treatment with *Trichoderma viride* or Imidacloprid 70 WS or Chlothianidin at 9 ml/kg can be effective in reducing population buildup. Aphids are biologically controlled by several species of *coccinellids, chrysopids, syrphids* and the parasitoid *Aphelinus gossypii* (Timberlake). Application of safe and systemic insecticides like Monochrotophos 36SL, Dimethate 30 EC, Endosulphan should be considered if the

**2.5** *Amrasca devastans* **(Distant) or** *Amrasca biguttula biguttula* **(Ishida) (Homoptera:** 

**Identification:** adults are usually less than 13 mm long, with slender, tapered bodies of various colors and legs with rows of sharp spines. Eggs are curved and nymphs are

**Life cycle and damage**: the common name of the pest is Indian cotton leafhopper or Indian cotton jassid. The female inserts eggs inside leaf veins and after 4 to 11 days the eggs hatch. Nymphs remain confined to the lower surface of leaves during day time. Nymphs' period lasted 7 - 21 days depending on the weather conditions. They have about eleven generations in a year. Both adult and the nymph stages suck the plants sap from under surfaces of the leaves and produce a salivary toxin which impair photosynthesis and cause the edges of the leaves to curl downward. Subsequently, the leaves become yellowish and then redden. Hairy varieties of cotton such as hirsute are less susceptible to the jassids. So, yield loss can be reduced by growing hairy varieties (Natarajan, 2007; Navarajan, 2007). *A. biguttula* 

**Monitoring:** monitor the presence of leafhoppers by brushing the foliage; watching for adults and nymphs to jump and fly from plant to plant. Leafhoppers are most sampled with a sweep net. Empty captured jassids into a container with 70% alcohol (or methylated spirits), and express counts as leafhoppers per sweep (one sweep per row) (Bailey, 2007).

**Economic and action thresholds:** The economic threshold is observing 2-3 adults or nymph per leaf; although for glabrous varieties the threshold may be lowered to one jassid per leaf. Threshold should consider when the margins of the leaves become yellow (Natarajan, 2007). **Control**: Natural enemies are not considered to have a significant effect on population of jassids although the parasitoid *Anagrus sp.* has been recorded, but it does not play any significant role in reducing the population. Applying systemic insecticides such as acetamiprid, acephate, so on or seed treatment with imidacloprid or Chlothianidin at 9 ml/kg give good control of jassids (Natarajan, 2007; Navarajan, 2007; Udikeri et al., 2007). also Aslam et al., (2004) declared that Confidor and Mospilan are effective against jassids.

**Identification:** adults are about 1 mm long with two pairs of white wings and light yellow bodies. Their bodies are covered with waxy powdery materials. Eggs are tiny, oval-shaped,

threshold is exceeded (Natarajan, 2007; Navarajan, 2007; Udikeri et al., 2007).

*biguttula* also damage severely other oilseed crops such as sunflower.

**2.6** *Bemisia tabaci* **(Genn.) (Hemiptera: Aleyrodidae)** 

amounts of honeydew is present (Yvette & Jensen, 2009).

flattened, pale yellowish green (Natarajan, 2007).

**Cicadellidae)** 

**Life cycle and damage**: *T. tabaci* is known as cotton seedling thrips. Adults prefer to lay their eggs in leaf, cotyledon, or flower tissues. Usually, cotton thrips destroy the cotyledons at first and then other parts of the crop including the bolls. Most damage occurs during early vegetative stage of the crop. Both adult and nymph feed on the under surface of the leaves make them thickened, blistered and bronzed due to continuous feeding. Developing bolls become brown due to development of necrotic patches (Natarajan, 2007; Yvette & Jensen, 2009). *S. dorsalis* can severely damage other oilseed crops such as sunflower.

**Monitoring:** monitoring should be started from seedling emergence of the crop and number of thrips on 20 - 30 plants counted weekly for every 50 ha (Yvette & Jensen, 2009). Monitor by picking and slapping a leaf on a white index card to see if the tiny specks move around. Open and microscopically examine the plant's growing point for thrips. Plucked growing points can also be dunked in alcohol to dislodge thrips (Bailey, 2007). Also, colored sticky traps can be used for monitoring thrips. Male thrips were most attracted to yellow sticky traps while female thrips were more attracted to pink sticky traps (Yaku et al., 2007).

**Economic and action thresholds:** The economic threshold from seedling stage until having six true leaves is when 10 adults or nymphs per plant is observed (Yvette & Jensen, 2009).

**Control**: in moderate infestations, biological control of the thrips by *Anthocoridae, Lygaidae*  and predator mites will be effective. Seed treatment with Imidacloprid 70 WS and Chlothianidin (Poncho 600 FS) at 9 ml/kg can protect cottonseeds from early season infestation (Udikeri et al., 2007). However, when high population of thrips recorded systemic insecticides (acetamiprid, imidacloprid and acephate) should be applied (Natarajan, 2007). Aslam et al., (2004) reported that Mospilan, Confidor and Tamaron were highly effective against thrips on cotton.

#### **2.4** *Aphis gossypii* **(Glover) (Homoptera: Aphididae)**

**Identification:** *A. gossypii* is commonly referred as cotton aphid. Adults are small (apterate 0.9 - 1.8 mm long and alate 1.1 - 1.8 mm long) and variable in color from greenish brown to orange or dirty yellow with soft body. Nymphs are small sizes of adults.

**Life cycle and damage**: The females reproduce nymphs parthenogenetically and viviparous which become adults in 7 - 9 days. Cotton aphid is the most common aphid pest infests the cotton seedlings. They are phloem feeders, causing direct leaf crumpling and downward curling with severe attack. Adults and nymphs suck sap from the under surface of the leaves, produce honeydew, indirectly decrease cotton fiber quality and may burn the leaves. Black sooty mould develops on the honeydew interfere photosynthesis of the leaves. Also, they are known as a vector of viruses (Vennila, n.d.). Wilson (2011) reported that aphids transmit plant virus Cotton Bunchy Top appearing in fields across the Australia.

**Monitoring:** monitor adults and nymphs on the underside of main stem leaves, 3 - 4 nodes below the plant terminal. Presence of ants may indicate presence of aphids. Early detection of aphids is important as they can multiply rapidly. If a high proportion of plants have only the winged form of aphids, recheck within a few days to see if they have settled and young are being produced. Yellow traps are useful for monitoring winged aphids. The presence and abundance of natural enemies should also be recorded (Yvette & Jensen, 2009).

**Life cycle and damage**: *T. tabaci* is known as cotton seedling thrips. Adults prefer to lay their eggs in leaf, cotyledon, or flower tissues. Usually, cotton thrips destroy the cotyledons at first and then other parts of the crop including the bolls. Most damage occurs during early vegetative stage of the crop. Both adult and nymph feed on the under surface of the leaves make them thickened, blistered and bronzed due to continuous feeding. Developing bolls become brown due to development of necrotic patches (Natarajan, 2007; Yvette &

**Monitoring:** monitoring should be started from seedling emergence of the crop and number of thrips on 20 - 30 plants counted weekly for every 50 ha (Yvette & Jensen, 2009). Monitor by picking and slapping a leaf on a white index card to see if the tiny specks move around. Open and microscopically examine the plant's growing point for thrips. Plucked growing points can also be dunked in alcohol to dislodge thrips (Bailey, 2007). Also, colored sticky traps can be used for monitoring thrips. Male thrips were most attracted to yellow sticky

**Economic and action thresholds:** The economic threshold from seedling stage until having six true leaves is when 10 adults or nymphs per plant is observed (Yvette & Jensen, 2009).

**Control**: in moderate infestations, biological control of the thrips by *Anthocoridae, Lygaidae*  and predator mites will be effective. Seed treatment with Imidacloprid 70 WS and Chlothianidin (Poncho 600 FS) at 9 ml/kg can protect cottonseeds from early season infestation (Udikeri et al., 2007). However, when high population of thrips recorded systemic insecticides (acetamiprid, imidacloprid and acephate) should be applied (Natarajan, 2007). Aslam et al., (2004) reported that Mospilan, Confidor and Tamaron were

**Identification:** *A. gossypii* is commonly referred as cotton aphid. Adults are small (apterate 0.9 - 1.8 mm long and alate 1.1 - 1.8 mm long) and variable in color from greenish brown to

**Life cycle and damage**: The females reproduce nymphs parthenogenetically and viviparous which become adults in 7 - 9 days. Cotton aphid is the most common aphid pest infests the cotton seedlings. They are phloem feeders, causing direct leaf crumpling and downward curling with severe attack. Adults and nymphs suck sap from the under surface of the leaves, produce honeydew, indirectly decrease cotton fiber quality and may burn the leaves. Black sooty mould develops on the honeydew interfere photosynthesis of the leaves. Also, they are known as a vector of viruses (Vennila, n.d.). Wilson (2011) reported that aphids

**Monitoring:** monitor adults and nymphs on the underside of main stem leaves, 3 - 4 nodes below the plant terminal. Presence of ants may indicate presence of aphids. Early detection of aphids is important as they can multiply rapidly. If a high proportion of plants have only the winged form of aphids, recheck within a few days to see if they have settled and young are being produced. Yellow traps are useful for monitoring winged aphids. The presence

Jensen, 2009). *S. dorsalis* can severely damage other oilseed crops such as sunflower.

traps while female thrips were more attracted to pink sticky traps (Yaku et al., 2007).

highly effective against thrips on cotton.

**2.4** *Aphis gossypii* **(Glover) (Homoptera: Aphididae)** 

orange or dirty yellow with soft body. Nymphs are small sizes of adults.

transmit plant virus Cotton Bunchy Top appearing in fields across the Australia.

and abundance of natural enemies should also be recorded (Yvette & Jensen, 2009).

**Economic and action thresholds:** The economic threshold level in the first open boll stage until harvest is the time if 50% of the plants (counted randomly) are affected or 10% trace amounts of honeydew is present (Yvette & Jensen, 2009).

**Control:** planting resistant or tolerant varieties which are densely hairy and with stiff leaves are reliable control technique. Seed treatment with *Trichoderma viride* or Imidacloprid 70 WS or Chlothianidin at 9 ml/kg can be effective in reducing population buildup. Aphids are biologically controlled by several species of *coccinellids, chrysopids, syrphids* and the parasitoid *Aphelinus gossypii* (Timberlake). Application of safe and systemic insecticides like Monochrotophos 36SL, Dimethate 30 EC, Endosulphan should be considered if the threshold is exceeded (Natarajan, 2007; Navarajan, 2007; Udikeri et al., 2007).

#### **2.5** *Amrasca devastans* **(Distant) or** *Amrasca biguttula biguttula* **(Ishida) (Homoptera: Cicadellidae)**

**Identification:** adults are usually less than 13 mm long, with slender, tapered bodies of various colors and legs with rows of sharp spines. Eggs are curved and nymphs are flattened, pale yellowish green (Natarajan, 2007).

**Life cycle and damage**: the common name of the pest is Indian cotton leafhopper or Indian cotton jassid. The female inserts eggs inside leaf veins and after 4 to 11 days the eggs hatch. Nymphs remain confined to the lower surface of leaves during day time. Nymphs' period lasted 7 - 21 days depending on the weather conditions. They have about eleven generations in a year. Both adult and the nymph stages suck the plants sap from under surfaces of the leaves and produce a salivary toxin which impair photosynthesis and cause the edges of the leaves to curl downward. Subsequently, the leaves become yellowish and then redden. Hairy varieties of cotton such as hirsute are less susceptible to the jassids. So, yield loss can be reduced by growing hairy varieties (Natarajan, 2007; Navarajan, 2007). *A. biguttula biguttula* also damage severely other oilseed crops such as sunflower.

**Monitoring:** monitor the presence of leafhoppers by brushing the foliage; watching for adults and nymphs to jump and fly from plant to plant. Leafhoppers are most sampled with a sweep net. Empty captured jassids into a container with 70% alcohol (or methylated spirits), and express counts as leafhoppers per sweep (one sweep per row) (Bailey, 2007).

**Economic and action thresholds:** The economic threshold is observing 2-3 adults or nymph per leaf; although for glabrous varieties the threshold may be lowered to one jassid per leaf. Threshold should consider when the margins of the leaves become yellow (Natarajan, 2007).

**Control**: Natural enemies are not considered to have a significant effect on population of jassids although the parasitoid *Anagrus sp.* has been recorded, but it does not play any significant role in reducing the population. Applying systemic insecticides such as acetamiprid, acephate, so on or seed treatment with imidacloprid or Chlothianidin at 9 ml/kg give good control of jassids (Natarajan, 2007; Navarajan, 2007; Udikeri et al., 2007). also Aslam et al., (2004) declared that Confidor and Mospilan are effective against jassids.

#### **2.6** *Bemisia tabaci* **(Genn.) (Hemiptera: Aleyrodidae)**

**Identification:** adults are about 1 mm long with two pairs of white wings and light yellow bodies. Their bodies are covered with waxy powdery materials. Eggs are tiny, oval-shaped,

Oilseed Pests 125

stems to obtain moisture. These pests prefer inside the bolls and they occasionally go through the leaves of cotton plants or in a single cotton boll, resulting in reduction of seed weight and seed viability in late bolls. A generation from egg to adult can be completed in 20 days, and the pest has three to four generations per year (Smith & Brambila, 2008).

**Monitoring:** monitor by visual observation and count the number of adults and nymphs. Seed bugs usually found in open bolls and boll opening onwards (Brien, 2010). Also, UVlight traps can be placed in areas related to potential pathways for *O. hyalinipennis* (Derksen

**Control:** Burning old cotton stalks with bolls may limit future damage by the cottonseed bug. Removal of all weeds or alternative malvaceous host plants near cotton fields is recommended. The cottonseed bug does not normally require control as damage tends to be only to seeds in late bolls. However, Chlorpyrifos-ethyl/hexaflumuron, Dimethoate, Biphenthrin, Endosulfan, Malathion, Methomyl/diflubenzuron and Neem are insecticides

**Identfication:** Adults of green mirid are about 7mm long, pale green with long antennae. They have sparse setae on their scutellum and pronotum. Females can be distinguished from males by the presence of a median cleft which runs along the mid ventral line of the last abdominal segment. Eggs are about 1.5 mm long, banana shaped, narrowing to a neck below the operculum. Nymphs are the small size of adults; newly hatched nymphs about 1.5–2 mm long and larger nymphs (4th and 5th stage) can be up to 7mm long. They are

**Life cycle and damage:** Females lay eggs singly within the plant tissue on cotton plants. This species showed a tendency to lay eggs at the distal end of the petioles on the upper one third of the plant. It has four to six nymphal stages. Adults and nymphs cause early season damage to terminals and buds and mid season damage to squares and small bolls; cause blackening, death of young plants terminals and rapid square loss. Bolls that are damaged during the first 10 days of development will be shed, while bolls damaged later than this will be retained but not continue normal development. Black, shiny spots indicate feeding sites on the outside of bolls. When sliced open, warty growths and discolouration of the immature lint can be seen within the boll. So, they cause both direct damage (destruction of terminals, leaves, bolls and branch primordia), and indirect damage (deformed plants) to cotton plants. From first flower until the time when approximately 60% of bolls are 20 days old, the crop is most susceptible to fruit loss that causes yield losses (McColl et al., 2011).

**Monitoring:** as mirids are very mobile and easily disturbed during monitoring so sample fruit retention and types of plant damage such as tip damage (early season) and boll damage (mid season). Beat sheet or sweep net techniques have proven to be the best

**Economic and action thresholds**: Threshold for *C. dilutus* ranges from 0.5 to 4 mirids per meter of row, depending on the crop stage, sampling technique (visual or beat sheet) and

sampling methods to find nymphs and adults, respectively (McColl et al., 2011).

climatic conditions (McColl et al., 2011).

**Economic and action thresholds**: No action threshold has been set for *O. hyalinipennis.*

available for use against the cottonseed bug (Brien, 2010; USDA, 2010).

characterized by their distinctive red tipped antennae (McColl et al., 2011).

**2.8** *Creontiades dilutus* **(Stal) (Hemiptera: Miridae)**

et al., 2009).

with about 0.25 mm diameter and stand vertically on the leaf surface, eggs at first are white then turn to brown. Nymphs' first instar is 0.3 mm length and the second instar has legs pulled up under its body and other immature stages are sessile. The last nymphal instar develops red eye spots and often is called the pupal stage (Bailey, 2007).

**Life cycle and damage**: the female lays two types of eggs; one that have not been fertilized and these eggs will result in male offspring. However, fertilized eggs will result in female offspring. Eggs are laid on the under surface of the leaves where the nymphs can suck the plants sap. The incubating time is different due to the season; in the summer eggs hatch after 3-5 days and nymphal period occupy about 9-14 days. However, for winter this period is 5-33 and 17-53 days, respectively. *B. tabaci* has the pupal stage which prolongs approximately 2-8 days and the life cycle ranges from 14-107 days depending on the weather conditions. Whiteflies are found on the under surface of the leaves. They directly feed from the crop, produce honeydew, developing sooty mould and also can transmit viruses (Natarajan, 2007; Navarajan, 2007). *B. tabaci* transmits plant viruses in seven distinct virus groups including: geminiviruses, closteroviruses, carlaviruses, potyviruses, nepoviruses, luteoviruses and a DNA-containing rod-shaped virus. Cotton followed by soybean have been affected by one or more whitefly transmitted viral diseases (Oliveira et al., 2001). They cause contamination of lint through the excretion of honeydew. Their honeydew is considered to be worse than aphid honeydew because it has a lower melting point and during the processing stage, can cause machinery to gum up and overheat (Yvette & Jensen, 2009). Whiteflies can severely damage other oilseed crops such as sunflower.

**Monitoring:** Monitoring is done by visual counting of nymphs and adults and catching with suction traps or yellow sticky traps. The latter are especially effective in detecting low density populations. Sample the population of larvae per leaf (Ohnesorge & Rapp, 1986).

**Economic and action thresholds**: the economic threshold is observing 5-10 nymphs or adults per leaf (Navarajan, 2007). Ellsworth & Martinez-Carrillo (2001) declared that based on comparative researches and observations in cotton two adults per leaf in Thailand, 6–8 adults in India, and ca. six adults per leaf in the Sudan were appropriate action thresholds.

**Control**: *Eretrmocerus mundus* (Mercet) and *Enacarsia* sp. are special parasites of *B. tabaci*. Also, the predators *Amblyseius sp.* (predatary mite), the green lacewing bug (*Chrysoperala sp.*) the coccinellids *Brumus sp., Scymnus sp.* and *Menochilus sp.* play important role in reducing whitefly population. Spray application of systemic insecticides can be effective; also neem oil can control whiteflies build up (Natarajan, 2007; Navarajan, 2007). In addition, Aslam et al., (2004) recommended Mospilan and Actara, as a good control agent against this pest.

#### **2.7** *Oxycarenus hyalinipennis* **(Costa) (Hemiptera: Lygaeidae)**

**Identfication:** Adults' measure 4-4.3 mm long; their thorax, head, antennae, and femora are black and wings folded flat on the back and they are translucent white. Males are slightly smaller than females. Nymph has pink to red abdomens. All stages are characterized by a powerful smell when crushed (USDA, 2010).

**Life cycle and damage:** the cottonseed bug is a major economic threat to cotton. The eggs are laid in open bolls and nymphs can be found in clusters among the lint. This species has five nymphal instars. Adults and nymphs suck sap from mature seeds and leaves of young

with about 0.25 mm diameter and stand vertically on the leaf surface, eggs at first are white then turn to brown. Nymphs' first instar is 0.3 mm length and the second instar has legs pulled up under its body and other immature stages are sessile. The last nymphal instar

**Life cycle and damage**: the female lays two types of eggs; one that have not been fertilized and these eggs will result in male offspring. However, fertilized eggs will result in female offspring. Eggs are laid on the under surface of the leaves where the nymphs can suck the plants sap. The incubating time is different due to the season; in the summer eggs hatch after 3-5 days and nymphal period occupy about 9-14 days. However, for winter this period is 5-33 and 17-53 days, respectively. *B. tabaci* has the pupal stage which prolongs approximately 2-8 days and the life cycle ranges from 14-107 days depending on the weather conditions. Whiteflies are found on the under surface of the leaves. They directly feed from the crop, produce honeydew, developing sooty mould and also can transmit viruses (Natarajan, 2007; Navarajan, 2007). *B. tabaci* transmits plant viruses in seven distinct virus groups including: geminiviruses, closteroviruses, carlaviruses, potyviruses, nepoviruses, luteoviruses and a DNA-containing rod-shaped virus. Cotton followed by soybean have been affected by one or more whitefly transmitted viral diseases (Oliveira et al., 2001). They cause contamination of lint through the excretion of honeydew. Their honeydew is considered to be worse than aphid honeydew because it has a lower melting point and during the processing stage, can cause machinery to gum up and overheat (Yvette & Jensen, 2009). Whiteflies can severely damage other oilseed crops such as sunflower.

**Monitoring:** Monitoring is done by visual counting of nymphs and adults and catching with suction traps or yellow sticky traps. The latter are especially effective in detecting low density populations. Sample the population of larvae per leaf (Ohnesorge & Rapp, 1986).

**Economic and action thresholds**: the economic threshold is observing 5-10 nymphs or adults per leaf (Navarajan, 2007). Ellsworth & Martinez-Carrillo (2001) declared that based on comparative researches and observations in cotton two adults per leaf in Thailand, 6–8 adults in India, and ca. six adults per leaf in the Sudan were appropriate action thresholds. **Control**: *Eretrmocerus mundus* (Mercet) and *Enacarsia* sp. are special parasites of *B. tabaci*. Also, the predators *Amblyseius sp.* (predatary mite), the green lacewing bug (*Chrysoperala sp.*) the coccinellids *Brumus sp., Scymnus sp.* and *Menochilus sp.* play important role in reducing whitefly population. Spray application of systemic insecticides can be effective; also neem oil can control whiteflies build up (Natarajan, 2007; Navarajan, 2007). In addition, Aslam et al., (2004) recommended Mospilan and Actara, as a good control agent against this pest.

**Identfication:** Adults' measure 4-4.3 mm long; their thorax, head, antennae, and femora are black and wings folded flat on the back and they are translucent white. Males are slightly smaller than females. Nymph has pink to red abdomens. All stages are characterized by a

**Life cycle and damage:** the cottonseed bug is a major economic threat to cotton. The eggs are laid in open bolls and nymphs can be found in clusters among the lint. This species has five nymphal instars. Adults and nymphs suck sap from mature seeds and leaves of young

**2.7** *Oxycarenus hyalinipennis* **(Costa) (Hemiptera: Lygaeidae)**

powerful smell when crushed (USDA, 2010).

develops red eye spots and often is called the pupal stage (Bailey, 2007).

stems to obtain moisture. These pests prefer inside the bolls and they occasionally go through the leaves of cotton plants or in a single cotton boll, resulting in reduction of seed weight and seed viability in late bolls. A generation from egg to adult can be completed in 20 days, and the pest has three to four generations per year (Smith & Brambila, 2008).

**Monitoring:** monitor by visual observation and count the number of adults and nymphs. Seed bugs usually found in open bolls and boll opening onwards (Brien, 2010). Also, UVlight traps can be placed in areas related to potential pathways for *O. hyalinipennis* (Derksen et al., 2009).

**Economic and action thresholds**: No action threshold has been set for *O. hyalinipennis.*

**Control:** Burning old cotton stalks with bolls may limit future damage by the cottonseed bug. Removal of all weeds or alternative malvaceous host plants near cotton fields is recommended. The cottonseed bug does not normally require control as damage tends to be only to seeds in late bolls. However, Chlorpyrifos-ethyl/hexaflumuron, Dimethoate, Biphenthrin, Endosulfan, Malathion, Methomyl/diflubenzuron and Neem are insecticides available for use against the cottonseed bug (Brien, 2010; USDA, 2010).

#### **2.8** *Creontiades dilutus* **(Stal) (Hemiptera: Miridae)**

**Identfication:** Adults of green mirid are about 7mm long, pale green with long antennae. They have sparse setae on their scutellum and pronotum. Females can be distinguished from males by the presence of a median cleft which runs along the mid ventral line of the last abdominal segment. Eggs are about 1.5 mm long, banana shaped, narrowing to a neck below the operculum. Nymphs are the small size of adults; newly hatched nymphs about 1.5–2 mm long and larger nymphs (4th and 5th stage) can be up to 7mm long. They are characterized by their distinctive red tipped antennae (McColl et al., 2011).

**Life cycle and damage:** Females lay eggs singly within the plant tissue on cotton plants. This species showed a tendency to lay eggs at the distal end of the petioles on the upper one third of the plant. It has four to six nymphal stages. Adults and nymphs cause early season damage to terminals and buds and mid season damage to squares and small bolls; cause blackening, death of young plants terminals and rapid square loss. Bolls that are damaged during the first 10 days of development will be shed, while bolls damaged later than this will be retained but not continue normal development. Black, shiny spots indicate feeding sites on the outside of bolls. When sliced open, warty growths and discolouration of the immature lint can be seen within the boll. So, they cause both direct damage (destruction of terminals, leaves, bolls and branch primordia), and indirect damage (deformed plants) to cotton plants. From first flower until the time when approximately 60% of bolls are 20 days old, the crop is most susceptible to fruit loss that causes yield losses (McColl et al., 2011).

**Monitoring:** as mirids are very mobile and easily disturbed during monitoring so sample fruit retention and types of plant damage such as tip damage (early season) and boll damage (mid season). Beat sheet or sweep net techniques have proven to be the best sampling methods to find nymphs and adults, respectively (McColl et al., 2011).

**Economic and action thresholds**: Threshold for *C. dilutus* ranges from 0.5 to 4 mirids per meter of row, depending on the crop stage, sampling technique (visual or beat sheet) and climatic conditions (McColl et al., 2011).

Oilseed Pests 127

**Identification:** The moth is small and dark brown with blackish bands on the forewings, and hind wings are silvery grey. Eggs are flattened oval and striate about 0.5 mm long, 0.25 mm wide. The larvae are pinkish with dark brown head and about 15 mm length. Pupae are in a thin silken cocoon among the lint inside a seed, in between bracts or in cracks in the soil. **Life cycle and damage:** The pink bollworm female lays the eggs on the bolls or in between bracts or on buds and flowers. After 4-25 days, due to the weather conditions, eggs hatch and larvae crawl to the bolls. Larva full grown in 25-35 days and the pupal period is about 6-20 days. The larvae feed early in the season from the inside of the green bolls. Seeds being destroyed in addition to retardation of lint development, lint weakened and stained both inside the boll and in the gin, causing lint yield losses. In addition, infested bolls open

**Monitoring:** monitoring can be done with pheromone baited traps as well as by sampling

**Economic and action thresholds**: the economic threshold is 8 moths per trap (glossyplure pheromone traps) per day for 3 consecutive days. The number of traps should be 5 per ha or

**Control:** Biological control of larvae with *Chelonus* sp., *Camptothlipsis* sp., and *C. blackburni*  (Cam.) is effective against overwintering stage. Parasitoids include *Trichogramma brasiliensis*  (Ashm.), *Bracon kirkpatricki* (Wilkinson), *Chelonus blackburni* (Cameron); predatory mites such as *Pyemotes ventricosus* (Newport) and *P. herfsi* (Oudemans) are widely reported on reducing bollworm population. Also, entomopathogenic nematodes (Rhabditida: Steinernematidae) such as S*teinernema riobravis* (Cabanillas, Poinar and Raulston) and *Steinernema carpocapsae* (Weiser) may control pests infestations. Applying insecticides is advised if the threshold is exceeded. Application of carbaryl 50 WP, quinalphos 25 EC, profenofos 50 EC, or fumigation of seeds with aluminum phosphide at 18 tablets per 100 cu.

flowers and bolls to record damage levels in cotton fields (Lykouressisa et al., 2005).

m. is recommended (Gouge et al., 1998; Navarajan, 2007; Salama, 1983; Vennila, n.d.).

**2.11** *Heliothis armigera* **(Hübner) and** *Heliothis punctigera* **(Wallengren) (Lepidoptera:** 

**Identification:** moth of *H. armigera* is about 35 mm long, with a small pale patch in the dark section of the hind wing; while in *H. punctigera* the dark section is uniform. Eggs of both species are 0.5 mm in diameter, sculptured with longitudinal ribs. *H. armigera* larvae have white hairs around head; medium larvae have saddle of dark pigment on 4th segment from head, and have dark legs. *H. punctigera* larvae have black hairs on the prothorax, dark triangles on the first abdominal segment with light legs. Pupa is smooth surfaced, brown, rounded both anterior and posterior with two tapering parallel spines at posterior tip

**Life cycle and damage:** *H. punctigera* is known as native budworm; and *H. armigera* is the cotton bollworm or corn earworm. *H. armigera* occurs throughout the Africa, Western Europe and Australian pacific region. The adults lay their eggs on young terminal branches of the cotton and after 2 or 3 days the eggs hatch and larvae go through the young leaves and flower buds. So, they burrow fruit and feed from developing seeds and fibers until

**2.10** *Pectinophora gossypiella* **(Saunders) (Lepidoptera: Gelechiidae)** 

prematurely and are invaded by saprophytic fungi.

**Noctuidea)** 

(Vennila, n.d.).

10% infested flowers or bolls with live larvae (Sabesh, 2004).

**Control:** damsel bugs, big-eyed bugs, predatory shield bugs, as well as lynx, night stalker and jumping spiders are known to feed on mirid adults, nymphs and eggs (Yvette & Jensen, 2009). *C. dilutus* is coincidentally controlled in cotton by applications of insecticides targeted at other pests such as *Heliothis* spp. (McColl et al., 2011).

Some other important sucking insect pests of cottonseeds are:

Occasionally green peach aphid, *Myzus persicae* (Sulzer) and cowpea aphid, *Aphis craccivora* (Koch) (Hompotera: Aphididae), infest young cotton. Green vegetable bug, *Nezara viridula* (L.) (Hemiptera: Pentatomidae), pale cotton stainer, *Dysdercus sidae* (Montr.) and red cotton bug, *Dysdercus cingulatus* (F.) (Hemiptera: Pyrrhocoridae) sometimes cause economic damage and heavy crop losses in some regions. Also, brown mirid, *Creontiades pacificus* (Stål) (Hemiptera: Miridae) and cottonseed bug, *Oxycarenus luctuosus* (Montrouzier) (Hemiptera: Lygaeidae) can cause damage to the cotton but the damage of these pests is minor and doesn't require control.
