**5.4** *Bagrada hilaris* **(Burmeister) (Hemiptera: Pentatomidae)**

**Identification:** painted bug adult is black with orange spots and markings called painted bug. These stink bugs are about 5–7 mm long. Females are larger than the males and both have distinctive black. The eggs are oval-shaped and off-white in color developing to an orange color when growth. Nymphs color changed as they develop from bright orange to red with dark markings, gradually acquiring the coloration of the adult. Wing pads are visible in the last instar nymph and gradually developed as they grow (Barlow, n.d.).

**Life cycle and damage**: Females lay about 50-80 eggs singly or in clusters of approximately 2-4 eggs during their lifetime. The eggs are laid on leaves or on the soil underneath host plants which hatch after 5-8 days. It has five nymphal stages. All stages of painted bugs can be found on a plant and both adults and nymphs suck sap from all parts of the plant. Young plants wilt and wither as a result of the attack. Also, adults excrete a resinous substance which spoils the pods. They often stunt the growth of newly formed central shoots or heads of plants. Quality and quantity (31% losses) of yield is affected when grown up plants are infected. Harvested crop in threshing floor is also infested (TIFP, n.d.-b)

**Monitoring:** monitor egg masses; if parasitized egg masses (black ones) are found, treatment for newly hatched nymphs might not be necessary. Also, monitor by beating or by shaking the vines on the cloth and count number of nymphs and adults.

**Economic and action thresholds:** In Africa where this insect comes from originally, the economic threshold is one bug/10 ft.² on plants in the early growth stage increasing to 3 bug/10 ft.² on mature plants (Barlow, n.d.).

**Control**: Deep ploughing; early sowing; irrigation of the crop and quick threshing of the harvested crop are the cultural techniques that can reduce pest attack. Burn the remains of mustard crop and conservation of bio-control agents like *Alophara* spp. can control painted bug population. Spraying malathion 50 EC, Endosulphan 35 EC, and Dimethothiate 30 EC should be considered if the threshold is exceeded (TIFP, n.d.-b).

#### **5.5** *Psylliodes chrysocephala* **(L.) (Coleoptera, Chrysomelidae)**

**Identification:** Cabbage stem flea beetle is about 3-4.5 mm long, blue-black or light brown. Eggs are oval-shaped and about 0.9 x 0.4 mm, pale orange. The larvae are distinguished from other pests by their black head and black plate at the tail end (Jellis, 2003).

**Life cycle and damage:** females lay their eggs on the surface or in the cracks of the ground, singly or in clusters of 2 to 8 in the immediate vicinity of the stems of plants. The hatching larvae bore into petioles and continue feeding close under the surface. Later, larvae move into the main stem to feed under the growing point. The feeding injury appears as holes or small pits in the cotyledons and leaves. The beetles fly to canola, rapeseed and other mustards, moving into fields just as the seedlings emerge. They feed on the emerging cotyledon and first true leaves of the young plant. Feeding injury can result in plant death and stand loss. Flea beetles feed most actively when the weather is sunny, warm and dry. They overwinter as adult and have one generation per year.

Other flea beetles that are of increasing importance are: *Psylliodes luteola* (Müller) (Wessex flea beetle) which attacks crops in the autumn; *Phyllotreta cruciferae* (Goeze)*, Phyllotreta* 

**Identification:** painted bug adult is black with orange spots and markings called painted bug. These stink bugs are about 5–7 mm long. Females are larger than the males and both have distinctive black. The eggs are oval-shaped and off-white in color developing to an orange color when growth. Nymphs color changed as they develop from bright orange to red with dark markings, gradually acquiring the coloration of the adult. Wing pads are

**Life cycle and damage**: Females lay about 50-80 eggs singly or in clusters of approximately 2-4 eggs during their lifetime. The eggs are laid on leaves or on the soil underneath host plants which hatch after 5-8 days. It has five nymphal stages. All stages of painted bugs can be found on a plant and both adults and nymphs suck sap from all parts of the plant. Young plants wilt and wither as a result of the attack. Also, adults excrete a resinous substance which spoils the pods. They often stunt the growth of newly formed central shoots or heads of plants. Quality and quantity (31% losses) of yield is affected when grown up plants are

**Monitoring:** monitor egg masses; if parasitized egg masses (black ones) are found, treatment for newly hatched nymphs might not be necessary. Also, monitor by beating or by

**Economic and action thresholds:** In Africa where this insect comes from originally, the economic threshold is one bug/10 ft.² on plants in the early growth stage increasing to 3

**Control**: Deep ploughing; early sowing; irrigation of the crop and quick threshing of the harvested crop are the cultural techniques that can reduce pest attack. Burn the remains of mustard crop and conservation of bio-control agents like *Alophara* spp. can control painted bug population. Spraying malathion 50 EC, Endosulphan 35 EC, and Dimethothiate 30 EC

**Identification:** Cabbage stem flea beetle is about 3-4.5 mm long, blue-black or light brown. Eggs are oval-shaped and about 0.9 x 0.4 mm, pale orange. The larvae are distinguished

**Life cycle and damage:** females lay their eggs on the surface or in the cracks of the ground, singly or in clusters of 2 to 8 in the immediate vicinity of the stems of plants. The hatching larvae bore into petioles and continue feeding close under the surface. Later, larvae move into the main stem to feed under the growing point. The feeding injury appears as holes or small pits in the cotyledons and leaves. The beetles fly to canola, rapeseed and other mustards, moving into fields just as the seedlings emerge. They feed on the emerging cotyledon and first true leaves of the young plant. Feeding injury can result in plant death and stand loss. Flea beetles feed most actively when the weather is sunny, warm and dry.

Other flea beetles that are of increasing importance are: *Psylliodes luteola* (Müller) (Wessex flea beetle) which attacks crops in the autumn; *Phyllotreta cruciferae* (Goeze)*, Phyllotreta* 

from other pests by their black head and black plate at the tail end (Jellis, 2003).

visible in the last instar nymph and gradually developed as they grow (Barlow, n.d.).

infected. Harvested crop in threshing floor is also infested (TIFP, n.d.-b)

shaking the vines on the cloth and count number of nymphs and adults.

should be considered if the threshold is exceeded (TIFP, n.d.-b).

They overwinter as adult and have one generation per year.

**5.5** *Psylliodes chrysocephala* **(L.) (Coleoptera, Chrysomelidae)** 

bug/10 ft.² on mature plants (Barlow, n.d.).

**5.4** *Bagrada hilaris* **(Burmeister) (Hemiptera: Pentatomidae)** 

*nigripes* (Fabricius)*,* (turnip flea beetles) attack crops in autumn and spring; and *Phyllotreta nemorum* (L.) (large striped flea beetle) which attacks crops in spring (Jellis, 2003).

**Monitoring:** mobile D-vac suction sampler can be used to sample cabbage stem flea beetles. Shoots enclosed within cylinders (0.25 m2 area) are shaken and excised on the ground and subsequently the area should vacuum for three minutes. Water traps can be placed on the ground around field perimeters to monitor their immigration to the crop. Also, damage level should be determined for estimating time of management (Alford, 2003)

**Economic and action thresholds:** action threshold is over 25% of the leaf area at the 1–2 true leaf growth stage; or over 50% of the leaf area at the 3–4 true leaf stage; or when the crop is growing more slowly than it is being destroyed. Also, if over 5 larvae/plant are present in the field or over 50% petioles damaged (Jellis, 2003; Knodel & Olson, 2002).

**Control**: early planting can protect crops from pest's infestations. The larvae are biologically controlled by *Tersilochus microgaster* (Szépligeti)*.* Seed Treatment with Chinook, Gaucho®, Helix®, Poncho® and Prosper® protect crops from early season infestation. If the threshold is exceeded application of a foliar insecticide reduce flea beetles population. Pyrethroid spray controls feeding adults and larvae that have not entered the main stem (Jellis, 2003).

#### **5.6** *Meligethes aeneus* **(F.) (Coleoptera: Nitidulidae)**

**Identification:** Pollen beetles are about 2-3 mm long, and black with a hint of metallic green. The eggs are elongated, glassy appearance verging on the milky-white. The larvae are up to 3 mm long and have a head capsule and six legs (Jellis, 2003).

**Life cycle and damage:** females lay their eggs in the buds and after 4-9 days the eggs hatch. The common name of pollen beetle is because both adults and larvae feed on the flowers, pollen and nectar and contributes to the pollination of the crop. Loss of pod sites albeit sometimes severe, rarely reduces winter oilseed rape yields. After opening all buds of winter crops, beetles migrate to other egg-laying sites, causing a second flush of migration to spring crops. Crops usually compensate for earlier losses, producing more and larger seeds on lower racemes. The adult overwinters at the edge of woodlands or in undergrowth. *M. aeneus* has two generations per year. Varietal associations and restored hybrids may lose more yields because male fertile plants are attacked and crosspollination is reduced. Spring crops are much more vulnerable than winter crops (Jellis, 2003).

**Monitoring:** During flowering, the beetles are attracted by the yellow color of host plants. So, *M. aeneus* can be monitored by yellow traps*.* Also, beat the main flowering racemes of plants over a white tray and count insect's number (Alford, 2003; Ruther & Thiemann, 1997).

**Economic and action thresholds:** For winter oilseed rape the action threshold is when: over 15 beetles/plant at green-yellow bud stage; over 5/plant for backward crops; over 2/plant for varietal associations is recorded. In the case of spring oilseed rape observing over 3beetles/plant at green bud stage is the time of controlling pollen beetles (Jellis, 2003).

**Control**: *Phradis interstitialis* (Thomson)*, Phradis morionellus* (Holmgren) and *Tersilochus heterocerus* (Thomson) can biologically control the larvae of pollen beetle. If thresholds are exceeded application of pyrethroid in green to yellow bud stages is advised (Jellis, 2003).

Oilseed Pests 159

**Monitoring:** monitor directly the crop from emergence and look for signs of pests activity,

**Economic and action thresholds:** ETL is when up to 26 larvae per plant is observed

**Control**: seed treatments by gamma-HCH or sprays of gamma-HCH, azinphos-methyl, azinphos-methyl plus demeton-S-methyl sulphone, chlorpyrifos or triazophos are effective against stem weevils (Graham & Gould, 1980). Carbofuran or phorate granules reduce larval infestations, but thiofanox granules and dimethoate sprays are ineffective (Evans, 2007).

**Identification:** Cabbage maggot or root maggot adults look like house flies but smaller, about 5 mm long, dark ash grey with a dark stripe along the top of the abdomen, and covered with black hairs and bristles (setae). The reddish purple eyes on males nearly touch in the centre of the head while female eyes are separated. In males, the presence of the basal brush of long setae (anteroventral setae) on the hind femur and by relatively shorter lateral setae of the 5th sternite processes. In the hind femur of females, the row of anteroventral setae is normally uneven and posteroventral setae are lacking. The eggs are white and about 1 mm diameter. The larva posterior extremity bears a crown of 10 small black membranous points, which is also visible on the pupae. The pupae are reddish

**Life cycle and damage**: The adults feed on nectar and lay their eggs close to plants of the genus *Brassica* on cool, moist soil. The eggs hatch into white maggots after about six days and the larvae feed for about three weeks on the roots and stems of the cabbage plants. The presence of larvae cause delay in plant growth accompanied by the withering of leaves which develop a bluish tinge. Sometimes 300 larvae can be found on one plant, damaging the inner parts of the main root and disrupting the transport of water and nutrients to the stem and leaves causing the death of many plants. The larvae mature in about 3-4 weeks, then leave the roots and pupate about 5-20 cm deep in the soil. This species has one or two generation a year (Wikipedia, 2011b). Dosdall et al., (1994) stated that the susceptibility of *Cruciferae* species to *D. radicum* is different. Plants of *B*. *rapa* were most susceptible to *Delia* spp.; intermediate susceptibility was observed for plants of *B*. *napus* and *B*. *juncea*; and plants of *B*. *alba* were least susceptible. The mechanism of resistance by cruciferous species to infestation by *Delia* spp. is antixenosis or non-

**Monitoring:** monitoring can be done by combination of yellow water pan traps and yellow

**Economic and action thresholds:** 21 eggs per plant is economic threshold for two week old

**Control**: remove weeds from the field two weeks before planting. Plant when there are fewer flies around to deposit eggs. If infested plants are found, they should be removed to

plants and about 100 eggs per plant, 4 weeks after planting (Bligaard et al., 1999).

sticky traps over an entire growing season (Broatch & Vernon, 1997).

prevent contamination of other plants.

presence of beetles, and shot holding of leaves.

**5.9** *Delia radicum* **(L.) (Diptera: Anthomyiidae)** 

(Winfield, 1961).

brown (Wikipedia, 2011b).

preference.

#### **5.7** *Ceutorhynchus assimilis* **(Paykull) (Coleoptera: Curculionidae)**

**Identification:** Adults of cabbage seed weevil are matt grey about 2-3.5 mm long, with a distinctive, long, narrow, downward-curved rostrum (snout) on the front of the head. The prothorax has a notch in the middle of the underside front edge where the rostrum can rest. There are seven segments in the antennal funiculus. The elytra are black, but the elytral interstices have fine hairs and greyish white scales which results in an overall grey appearance. Near the mid-line of the elytra, the interstices have 1-3 irregular rows of scales along their length. There is no tooth on the hind femora and all tarsi are black to dark brown, similar in color to the femora and tibiae. The tarsal claws are simple, not toothed. The eggs are creamy white, smooth, cylindrical with rounded ends, and about 0.6 mm long by 0.4 mm wide. They are often covered with a mucus-like material. The larva is vermiform, white with a brown head capsule. Pupae are about 2 mm long and occur in earthen cells in the soil. They are initially white, but then turn yellow (CABI, 2008).

**Life cycle and damage**: Cabbage seed weevil is univoltine; adults emerge from overwintering sites in the spring and migrate to rape crops to feed and oviposit. Females lay eggs into developing oilseed rape pods during flowering. A brown scar indicates the egglaying puncture, usually causing a kink in the pod. The larvae develop inside the pod and cause economic damage by eating the seeds. The abundance of cabbage seed weevil is greater in winter than spring. It has three larval instars (Jellis, 2003; Murchie et al., 1999).

**Monitoring:** installation of yellow water traps and beating the main flowering racemes of plants over a white tray and counting number of insects are techniques for monitoring cabbage seed weevil (Alford, 2003; Murchie et al., 1999).

**Economic and action thresholds:** action threshold is when over 0.5 beetle/plant in northern Britain or 1/plant elsewhere is observed (Jellis, 2003).

**Control**: Delaying sowing of spring crops reduces numbers of adults attracted and subsequently the number of laid eggs. *Trichomalus perfectus* (Walker)*, Mesopolobus morys*  (Walker) and *Stenomalina gracilis* (Walker) can biologically reduce the population. If the threshold is exceeded application of pyrethroid by petal fall and before too many eggs are laid can decrease the population buildup (Jellis, 2003).

#### **5.8** *Ceutorhynchus quadridens* **(Panzer) (Coleoptera: Curculionidae)**

**Identification:** Cabbage stem weevil adult is about 2 to 3.5 mm long, ashy grey. The Elytra is dorsally with a white rectangular spot; striae much narrower than the interstices which are covered in whitish scales. Larvae are about 3 to 5 mm, relatively elongated, white; with small light yellow head (Evans, 2007).

**Life cycle and damage**: females lay eggs in the petioles, young stems or along the main veins of the leaves over a period of weeks, depending both on temperature and crop stage. The eggs hatch after 5-8 days. The larvae tunnel their way into the mid rib of the leaf or the stem. Some diseases such as stem canker can gain access to the stem through the holes made by larvae as they leave the plant to pupate. Larval growth lasts 3 to 6 weeks until pupation, which takes place in the ground. Adults cause no obvious damage but can be found on plants. They infest a large percentage of plants and reduce vigor and yield. They overwinter as adult under lumps of earth or under plant debris (Evans, 2007).

**Identification:** Adults of cabbage seed weevil are matt grey about 2-3.5 mm long, with a distinctive, long, narrow, downward-curved rostrum (snout) on the front of the head. The prothorax has a notch in the middle of the underside front edge where the rostrum can rest. There are seven segments in the antennal funiculus. The elytra are black, but the elytral interstices have fine hairs and greyish white scales which results in an overall grey appearance. Near the mid-line of the elytra, the interstices have 1-3 irregular rows of scales along their length. There is no tooth on the hind femora and all tarsi are black to dark brown, similar in color to the femora and tibiae. The tarsal claws are simple, not toothed. The eggs are creamy white, smooth, cylindrical with rounded ends, and about 0.6 mm long by 0.4 mm wide. They are often covered with a mucus-like material. The larva is vermiform, white with a brown head capsule. Pupae are about 2 mm long and occur in earthen cells in

**Life cycle and damage**: Cabbage seed weevil is univoltine; adults emerge from overwintering sites in the spring and migrate to rape crops to feed and oviposit. Females lay eggs into developing oilseed rape pods during flowering. A brown scar indicates the egglaying puncture, usually causing a kink in the pod. The larvae develop inside the pod and cause economic damage by eating the seeds. The abundance of cabbage seed weevil is greater in winter than spring. It has three larval instars (Jellis, 2003; Murchie et al., 1999).

**Monitoring:** installation of yellow water traps and beating the main flowering racemes of plants over a white tray and counting number of insects are techniques for monitoring

**Economic and action thresholds:** action threshold is when over 0.5 beetle/plant in northern

**Control**: Delaying sowing of spring crops reduces numbers of adults attracted and subsequently the number of laid eggs. *Trichomalus perfectus* (Walker)*, Mesopolobus morys*  (Walker) and *Stenomalina gracilis* (Walker) can biologically reduce the population. If the threshold is exceeded application of pyrethroid by petal fall and before too many eggs are

**Identification:** Cabbage stem weevil adult is about 2 to 3.5 mm long, ashy grey. The Elytra is dorsally with a white rectangular spot; striae much narrower than the interstices which are covered in whitish scales. Larvae are about 3 to 5 mm, relatively elongated, white; with

**Life cycle and damage**: females lay eggs in the petioles, young stems or along the main veins of the leaves over a period of weeks, depending both on temperature and crop stage. The eggs hatch after 5-8 days. The larvae tunnel their way into the mid rib of the leaf or the stem. Some diseases such as stem canker can gain access to the stem through the holes made by larvae as they leave the plant to pupate. Larval growth lasts 3 to 6 weeks until pupation, which takes place in the ground. Adults cause no obvious damage but can be found on plants. They infest a large percentage of plants and reduce vigor and yield. They overwinter

**5.7** *Ceutorhynchus assimilis* **(Paykull) (Coleoptera: Curculionidae)** 

the soil. They are initially white, but then turn yellow (CABI, 2008).

cabbage seed weevil (Alford, 2003; Murchie et al., 1999).

Britain or 1/plant elsewhere is observed (Jellis, 2003).

laid can decrease the population buildup (Jellis, 2003).

small light yellow head (Evans, 2007).

**5.8** *Ceutorhynchus quadridens* **(Panzer) (Coleoptera: Curculionidae)** 

as adult under lumps of earth or under plant debris (Evans, 2007).

**Monitoring:** monitor directly the crop from emergence and look for signs of pests activity, presence of beetles, and shot holding of leaves.

**Economic and action thresholds:** ETL is when up to 26 larvae per plant is observed (Winfield, 1961).

**Control**: seed treatments by gamma-HCH or sprays of gamma-HCH, azinphos-methyl, azinphos-methyl plus demeton-S-methyl sulphone, chlorpyrifos or triazophos are effective against stem weevils (Graham & Gould, 1980). Carbofuran or phorate granules reduce larval infestations, but thiofanox granules and dimethoate sprays are ineffective (Evans, 2007).

#### **5.9** *Delia radicum* **(L.) (Diptera: Anthomyiidae)**

**Identification:** Cabbage maggot or root maggot adults look like house flies but smaller, about 5 mm long, dark ash grey with a dark stripe along the top of the abdomen, and covered with black hairs and bristles (setae). The reddish purple eyes on males nearly touch in the centre of the head while female eyes are separated. In males, the presence of the basal brush of long setae (anteroventral setae) on the hind femur and by relatively shorter lateral setae of the 5th sternite processes. In the hind femur of females, the row of anteroventral setae is normally uneven and posteroventral setae are lacking. The eggs are white and about 1 mm diameter. The larva posterior extremity bears a crown of 10 small black membranous points, which is also visible on the pupae. The pupae are reddish brown (Wikipedia, 2011b).

**Life cycle and damage**: The adults feed on nectar and lay their eggs close to plants of the genus *Brassica* on cool, moist soil. The eggs hatch into white maggots after about six days and the larvae feed for about three weeks on the roots and stems of the cabbage plants. The presence of larvae cause delay in plant growth accompanied by the withering of leaves which develop a bluish tinge. Sometimes 300 larvae can be found on one plant, damaging the inner parts of the main root and disrupting the transport of water and nutrients to the stem and leaves causing the death of many plants. The larvae mature in about 3-4 weeks, then leave the roots and pupate about 5-20 cm deep in the soil. This species has one or two generation a year (Wikipedia, 2011b). Dosdall et al., (1994) stated that the susceptibility of *Cruciferae* species to *D. radicum* is different. Plants of *B*. *rapa* were most susceptible to *Delia* spp.; intermediate susceptibility was observed for plants of *B*. *napus* and *B*. *juncea*; and plants of *B*. *alba* were least susceptible. The mechanism of resistance by cruciferous species to infestation by *Delia* spp. is antixenosis or nonpreference.

**Monitoring:** monitoring can be done by combination of yellow water pan traps and yellow sticky traps over an entire growing season (Broatch & Vernon, 1997).

**Economic and action thresholds:** 21 eggs per plant is economic threshold for two week old plants and about 100 eggs per plant, 4 weeks after planting (Bligaard et al., 1999).

**Control**: remove weeds from the field two weeks before planting. Plant when there are fewer flies around to deposit eggs. If infested plants are found, they should be removed to prevent contamination of other plants.

Oilseed Pests 161

**Identification:** Diamondback moth is small greyish with three white triangular spots along the inner-margin of the forewings. At rest the triangular markings of opposite wings appear as diamond shaped markings and hence the name. The larvae are pale green, body tapering

**Life cycle and damage**: females lay eggs on the lower leaves. The first instar larvae make tiny, irregular holes in the leaves. Diamondback moth is the most destructive pest of brassicasea throughout the world. Caterpillars feed on the foliage and make the leaves a withered appearance. Moths of later generations lay eggs higher on the plant and the larvae feed first on leaves, moving later to buds, flowers and developing seedpods. In later stages larvae bore holes in the leaves and the leaves may be eaten up completely. They also bores

**Monitoring:** monitor the presence of *P. xylostella* by pheromone traps or yellow sticky traps*.* 

**Economic and action thresholds:** economic threshold is when 25-30 larvae observed per square foot or 1-2 larvae per plant, and there is significant evidence of damage to flowers or

**Control**: bio-control agents such as *Cotesia plutellae* (Kurdjumov), *Diadegma mollipla*  (Holmgren), *Oomyzus sokolowski* (Kurdjumov)*,* and *Apanteles* sp. can control diamondback moth. When the threshold exceeded application of malathion, Trichlorfon, Endoslfan 35 EC, Diazinon 20 EC or triazophos is recommended (Manyangarirwa et al., 2009; TIFP, n.d.-b).

**Identification:** it is known as large white or cabbage butterfly. Forewings of the moth is mealy-white with dark pollination at base (wingspan 55-60 mm); females are larger than males. Wings at top with intensive black crescent limb reaching middle of outer margin and with 2 black rounded spots. They have sexual dimorphism and males just have 2 spots on the lower side of forewings. Hindwings have black stroke at anterior margin from above; grayish-yellow from below, with dense black pollination. The eggs are yellow skittleshaped. The larvae are yellowish green with yellow lines and black spots. Pupae are

**Life cycle and damage**: females lay eggs in batches on the lower side of leaves. After 4 to 16 days the eggs develop. Young caterpillars aggregate and scraping the lower side of leaves; older ones live individually, gnawing holes in leaves, contaminating the latter with excrement. In severe attacks thick veins only leave. Caterpillars have 5 instars and develop in 13-38 days. The pupa phase lasts 8-15 days. Diapausing pupae do not hibernate far from host plant localities on tree trunks and branches, fences etc. They have the ability to migrate in large numbers during the spring and autumn and have 2-3 generation (Navarajan, 2007). **Monitoring:** install pheromone traps for monitoring male moths and check the crop weekly

**Economic and action thresholds:** no action threshold has been set for *P. brassicae*.

Traps should be checked weekly and count the number of moths (TIFP, n.d.-b).

**5.12** *Plutella xylostella* **(L.) (Lepidoptera: Plutellidae)** 

into pods and feeds developing seed (TIFP, n.d.-b).

**5.13** *Pieris brassicae* **(Linn) (Lepidoptera: Pieridae)** 

after peak trap catches for the presence of larvae.

greenish-yellow with black dorsal and lateral dots (Navarajan, 2007).

slightly at both ends (TIFP, n.d.-b).

pods (Knodel et al., 2010).

## **5.10** *Dasineura brassicae* **(Diptera: Cecidomyiidae)**

**Identification:** The adults are 1-1.5 mm long, female with reddish abdomen; male, blackish. The larva is about 1.5 mm long, white or yellowish-white. Pupa is inside whitish cocoon about 1.4 to 2.1 mm long, at a depth of 3 cm, in the soil (Pavela & Kazda, 2007).

**Life cycle and damage**: Brassica pod midge females lay eggs in clusters through holes left by seed weevils in developing pods. After 4 days the eggs hatch and many small, white larvae occur in each affected pod. Midges appear during flowering; they feed on the internal wall of the pod valve (or on the seeds) by discharging saliva**.** They cause swelling and eventually pod burst. The larvae have 3 instars and they develop through 9 to 15 days, when they drop to the ground, bury themselves and form cocoons. Some will pupate; others may undergo diapauses for 1 to 4 years. They have about 3 to 4 generation (Jellis, 2003).

**Monitoring:** monitor *D. brassicae* by yellow or suction traps. Cardboard delta traps with sticky base plates have been used to monitor males (Alford, 2003; Pavela & Kazda, 2007).

**Economic and action thresholds:** No thresholds for treatment exist (Jellis, 2003).

**Control**: Blocking oilseed rape fields and rotation around the farm will reduce the impact of immigrant pests. *Omphale clypealis* (Thomson) and *Platygaster subuliformis* (Kieffer) may attack pod midge, killing up to 75% of larvae (Jellis, 2003). Calypso 480 SC has effects as contact and feeding poison with systemic impact, a non systemic pyrethroid insecticide protect the plants from beginning of flowering to full flowering (Pavela & Kazda, 2007).

#### **5.11** *Athalia proxima lugens* **Klug (Hymenoptera: Tenthredinidae)**

**Identification:** Adults are orange colored wasps with black head and smoky transparent wings. Larva is greenish black wrinkled body, with three legs of thoracic legs and seven pairs of prolegs. On slightest touch the larva falls to round and feigns death. The pupae formed in an earthen cocoon in the soil (Chowdhury, 2009; Navarajan, 2007).

**Life cycle and damage**: Mustard sawfly females lay eggs near the leaves margin. They attack the crop at early growth period when the seedlings are 3-4 week old. The larvae feed on the leaves of rapeseed and mustard making holes. In severe case larvae eat up entire lamina of leaf leaving behind the midribs. In extreme cases, this pest defoliates the plants completely. They devour the epidermis of the shoot, resulting in drying up of seedlings and failure to bear seeds in older plants. The yield loss is up to 5 to 18 % (Chowdhury, 2009).

**Monitoring:** monitor directly and count the number of larvae. Also, sweep netting and counting the number of adults can be used for monitoring sawflies.

**Economic and action thresholds:** no action threshold has been set for sawflies in mustard.

**Control**: Summer ploughing to destroy the pupae; early sowing; irrigation in seedling stage and severe cold reduce pest growth and are crucial for sawfly management. Conserving *Perilissus cingulator* (Morley) (parasites the grubs), and the bacterium *Serratia marcescens* (Bizio) infect the larvae of sawfly. Apply insecticides such as methyl parathion dust at the rate of 20-25 kg per hectare or Malathion 50 EC if the threshold is exceeded (TIFP, n.d.-b).

**Identification:** The adults are 1-1.5 mm long, female with reddish abdomen; male, blackish. The larva is about 1.5 mm long, white or yellowish-white. Pupa is inside whitish cocoon

**Life cycle and damage**: Brassica pod midge females lay eggs in clusters through holes left by seed weevils in developing pods. After 4 days the eggs hatch and many small, white larvae occur in each affected pod. Midges appear during flowering; they feed on the internal wall of the pod valve (or on the seeds) by discharging saliva**.** They cause swelling and eventually pod burst. The larvae have 3 instars and they develop through 9 to 15 days, when they drop to the ground, bury themselves and form cocoons. Some will pupate; others may undergo diapauses for 1 to 4 years. They have about 3 to 4 generation

**Monitoring:** monitor *D. brassicae* by yellow or suction traps. Cardboard delta traps with sticky base plates have been used to monitor males (Alford, 2003; Pavela & Kazda, 2007).

**Control**: Blocking oilseed rape fields and rotation around the farm will reduce the impact of immigrant pests. *Omphale clypealis* (Thomson) and *Platygaster subuliformis* (Kieffer) may attack pod midge, killing up to 75% of larvae (Jellis, 2003). Calypso 480 SC has effects as contact and feeding poison with systemic impact, a non systemic pyrethroid insecticide protect the plants from beginning of flowering to full flowering (Pavela & Kazda, 2007).

**Identification:** Adults are orange colored wasps with black head and smoky transparent wings. Larva is greenish black wrinkled body, with three legs of thoracic legs and seven pairs of prolegs. On slightest touch the larva falls to round and feigns death. The pupae

**Life cycle and damage**: Mustard sawfly females lay eggs near the leaves margin. They attack the crop at early growth period when the seedlings are 3-4 week old. The larvae feed on the leaves of rapeseed and mustard making holes. In severe case larvae eat up entire lamina of leaf leaving behind the midribs. In extreme cases, this pest defoliates the plants completely. They devour the epidermis of the shoot, resulting in drying up of seedlings and failure to bear seeds in older plants. The yield loss is up to 5 to 18 % (Chowdhury, 2009).

**Monitoring:** monitor directly and count the number of larvae. Also, sweep netting and

**Economic and action thresholds:** no action threshold has been set for sawflies in mustard. **Control**: Summer ploughing to destroy the pupae; early sowing; irrigation in seedling stage and severe cold reduce pest growth and are crucial for sawfly management. Conserving *Perilissus cingulator* (Morley) (parasites the grubs), and the bacterium *Serratia marcescens* (Bizio) infect the larvae of sawfly. Apply insecticides such as methyl parathion dust at the rate of 20-25 kg per hectare or Malathion 50 EC if the threshold is exceeded (TIFP, n.d.-b).

**Economic and action thresholds:** No thresholds for treatment exist (Jellis, 2003).

**5.11** *Athalia proxima lugens* **Klug (Hymenoptera: Tenthredinidae)** 

counting the number of adults can be used for monitoring sawflies.

formed in an earthen cocoon in the soil (Chowdhury, 2009; Navarajan, 2007).

about 1.4 to 2.1 mm long, at a depth of 3 cm, in the soil (Pavela & Kazda, 2007).

**5.10** *Dasineura brassicae* **(Diptera: Cecidomyiidae)** 

(Jellis, 2003).
