**5. Mustard**

*Brassica napus* L.: known as Canola, Rapeseed, Rutabaga, and Swede.

*Brassica juncea* L.: known as Brown and Oriental mustards, is grown commercially in Canada, the UK, Denmark and the USA.

*Brassica nigra* L.: known as Black mustard, is grown in Argentina, Chile, the USA and some European countries.

*Brassica alba* L. or *Brassica hirta* Moench.: known as White and yellow mustards, is grown wild in North Africa, the Middle East and Mediterranean Europe.

*Brassica rapa* L. or *Brassica campestris* L.*:* known as field mustard and turnip mustard.

#### **5.1 Snails:** *Cernuella virgata* **(Da Costa),** *Cochlicella acuta* **(Müller),** *Prietocella barbara*  **(Linnaeus) (Eupulmonata: Hygromiidae), and** *Theba pisana* **(Müller) (Eupulmonata: Helicidae); Slugs:** *Limax cinereoniger* **(Wolf) (Eupulmonata: Limacidae) and**  *Deroceras reticulatum* **(Müller) (Eupulmonata: Helicidae)**

**Identification:** snails are known as common white snail, pointed snail, small pointed snail and white Italian snail, respectively. The common names of slugs are black keeled slug and reticulated slug, respectively. Shell diameter of common white snail ranges from 10 to 15 mm. The coiled white shell has a brown band around the spiral in some individuals while others completely lack this banding. The umbilicus is open and circular. Under magnification, regular straight scratches are visible across the shell. The common white snail and white Italian snail are the same just umbilicus are different and the scratching per etches on the shell. Pointed snail is fawn, grey or brown with some white markings. The shell is conical in shape. The length of the shell of a mature snail is up to 18 mm. The ratio of the shell length to its diameter at the base is always greater than two. Small pointed snail shell is fawn, grey or brown in color. The length of the shell of a mature snail is up to 10 mm. The ratio of the shell length to its diameter at the base is always two or less. The black keeled slug is longer than 20 mm and has a uniform grey to black body color. This species has a prominent ridge (keel) running along the mid-dorsal line, from the mantle to the tip of the tail. The reticulated slug is black to brown, with elongated soft and slimy body about 40-60 mm long with a ridge down its back (Bailey, 2007).

Oilseed Pests 155

**Identification:** They are known as peach potato aphid and cabbage aphid, respectively. The eggs are usually elliptical in shape, initially yellow or green, but soon turn black. Nymphs look like to the viviparous adults. Winged aphids of *M. persicae* have a black head and thorax, and a yellowish green abdomen with a large dark patch dorsally. They measure 1.8-2.1 mm in length. The wingless forms are yellowish or greenish in color and about 1.7-2.0 mm long. They may have a medial and lateral green stripes. The cornicles are moderately long, unevenly swollen along their length, and match the body in color. The appendages are pale (Capinera, 2005). Wingless females of *B. brassicae* are about 2.1- 2.6 mm long oval shaped and the posterior end of the body tapers greatly. The pale green body is usually covered by white waxy powder. Underneath the wax there are eight dark brown or black spots located on the upper abdominal surface. They increase in size toward the posterior end. Winged females are a little smaller than the wingless forms and they are not covered with waxy powder. The head and thorax are dark brown to black. The yellowish green abdomen is with two dark spots on the dorsal anterior abdominal segments. Antennae are dark brown. Wings are short and stout with prominent veins

**Life cycle and damage**: Eggs of *M. persicae* are deposited on *Prunus* spp. trees, where they overwinter. After several generations when the aphid densities increased the winged forms produced and disperse to the summer hosts. However, *B. brassicae* is restricted to herbaceous Brassicaceae throughout its life cycle. They lay their eggs on the stems and leaves of cruciferous crops that remain in the field through the winter. Both of these aphids overwinter in the egg stage. Generally aphids feed by sucking sap; infested seedlings may become stunted and distorted. Continued feeding on mature plants causes wilting, yellowing and general stunting of the plants. For peach potato aphid only very heavy infestations cause direct damage. Numbers may increase after serious outbreaks of insecticide-resistant aphids on potatoes. Peach potato aphids transmit the beet western yellow virus, which causes temporary reddening of infected plants in spring. In the case of cabbage aphid, spring rape can become severely infested after mild winters and allow infestations on winter rape to increase to damaging levels. The cabbage aphid is a vector of 23 virus diseases of Brassicaceae. It carries cauliflower mosaic virus. Also, turnip mosaic

**Monitoring:** monitor weekly from flowering to grain fill of the crop. At least four sampling points of random 20 plants should be spread over the field and estimate the number of

**Economic and action thresholds:** *B. brassicae* action threshold is if over 13% of winter rape plants or over 4% of spring rape plants are infested before petal fall (Jellis, 2003). The threshold for *M. persicae* is correspondingly lower, at 25% of plants infested (Bailey, 2007).

**Control**: The parasitoid, *Diaeretiella rapae* (McIntosh) normally provides good control of cabbage aphid. Insecticide resistance has been observed for *M. persicae;* so expert advice on alternative insecticides should prepare. In the case of *B. brassicae* using a higher rate of

aphids per plant.Also, yellow traps can use for monitoring aphids (Bailey, 2007).

virus is carried by cabbage aphid and green peach aphid (Jellis, 2003).

pirimicarb plus added wetter is recommended (Jellis, 2003).

**5.3** *Myzus persicae* **(Sulzer) and** *Brevicoryne brassicae* **(Linnaeus) (Homoptera:** 

**Aphididae)** 

(Kessing & Mau, 1991).

**Life cycle and damage**: They are hermaphrodite so both male and female can lay eggs. Eggs are laid into moist soil and hatch after 2–4 weeks. They usually become sexually mature after one year. Feeding of these pests may retard development of young crops. They destroy crops by eating roots, leaves, stems and fruits. Damage to the canola during emergence, is usually difficult to detect if seedlings are chewed to the ground. Black keeled slug feed on the soil surface, as well as below the ground where they burrow down and attack germinating seeds. Young canola seedlings are particularly vulnerable. This species is of relatively greater importance in drier areas. For reticulated slug egg clusters are laid in the top soil. After 2 weeks the eggs hatch and the juveniles feed in winter and spring and aestivate over summer to become sexually mature at one year old (Micic et al., 2007).

**Monitoring:** monitor snails by square sampling quadrates. Quadrates are placed on the ground, the number of snails counted and convert to snails per square meter (Bailey, 2007).

**Economic and action thresholds:** action thresholds is observing 5 snails per m2 in emerging canola crops (Bailey, 2007). Micic et al., (2007) declared that action threshold for small pointed snail is 20 snails per m2, for common white snail 5 per m2, black keeled slug 1-2 per m2, reticulated slug 1-2 per m2 and in the case of white Italian snail it is 5 snails per m2.

**Control**: They can be controlled by birds and lizards. A parasitic fly, *Sarcophaga penicillata* (Villeneuve) is a bio-control agent for controlling pointed snail. However, the best way is baiting but it should be done in the cool moist condition, when snails are active. As bait may have some residue contamination in kernels so it must be completed at least 8 weeks before harvest. For 5-80 snails per m2 apply bait at 5 kg/ha and over 80 snails per m2 apply bait at 10 kg/ha. Metaldehyde-containing baits are frequently used for snail control (Bailey, 2007).

#### **5.2** *Lipaphis erysimi* **(Kalt) (Homoptera: Aphididae)**

**Identification:** Aphids are small, soft-bodied, pearl-shaped with a pair of cornicles projecting out from the fifth or sixth abdominal segment. Wingless female aphids are yellowish green, gray green or olive green with a white waxy bloom covering the body. The winged females have a dusky green abdomen with dark lateral stripes separating the body segments and dusky wing veins. Males are olive-green to brown in color (TIFP, n.d.-b).

**Life cycle and damage**: Mustard aphids infest the crops right from vegetative stage to pod stage. Both nymph and adults suck the sap from leaves, buds and pods. Curling may occur for infested leaves and at advanced stage plants may wither and die. Plants remain stunted and sooty molds grow on the honey dew excreted by the insects. The infected filed looks sickly and blighted in appearance. Rainy and humid weather help in accelerating the growth of insects. They have four nymphal instars (TIFP, n.d.-b).

**Monitoring:** install yellow stick trap to monitor aphid population (TIFP, n.d.-b).

**Economic and action thresholds:** The economic threshold level for mustard aphid for different regions of India is 23–25 aphids per plant (Chattopadhyay et al., 2005).

**Control**: planting tolerant or resistant varieties can reduce population build up. *Cocciniella septempunctata* (L.), *Menochilus sexmaculata* (F.), *H. variegata*, *Cheilomenes vicina* (Mulsant), *Sphaerophoria* spp., *Eristallis* spp., *Metasyrphis* spp., *Xanthogramma* spp. and *Syrphus* spp. are most efficient predators of the mustard aphid (TIFP, n.d.-b).

**Life cycle and damage**: They are hermaphrodite so both male and female can lay eggs. Eggs are laid into moist soil and hatch after 2–4 weeks. They usually become sexually mature after one year. Feeding of these pests may retard development of young crops. They destroy crops by eating roots, leaves, stems and fruits. Damage to the canola during emergence, is usually difficult to detect if seedlings are chewed to the ground. Black keeled slug feed on the soil surface, as well as below the ground where they burrow down and attack germinating seeds. Young canola seedlings are particularly vulnerable. This species is of relatively greater importance in drier areas. For reticulated slug egg clusters are laid in the top soil. After 2 weeks the eggs hatch and the juveniles feed in winter and spring and

aestivate over summer to become sexually mature at one year old (Micic et al., 2007).

**Monitoring:** monitor snails by square sampling quadrates. Quadrates are placed on the ground, the number of snails counted and convert to snails per square meter (Bailey, 2007). **Economic and action thresholds:** action thresholds is observing 5 snails per m2 in emerging canola crops (Bailey, 2007). Micic et al., (2007) declared that action threshold for small pointed snail is 20 snails per m2, for common white snail 5 per m2, black keeled slug 1-2 per m2, reticulated slug 1-2 per m2 and in the case of white Italian snail it is 5 snails per m2.

**Control**: They can be controlled by birds and lizards. A parasitic fly, *Sarcophaga penicillata* (Villeneuve) is a bio-control agent for controlling pointed snail. However, the best way is baiting but it should be done in the cool moist condition, when snails are active. As bait may have some residue contamination in kernels so it must be completed at least 8 weeks before harvest. For 5-80 snails per m2 apply bait at 5 kg/ha and over 80 snails per m2 apply bait at 10 kg/ha. Metaldehyde-containing baits are frequently used for snail control (Bailey, 2007).

**Identification:** Aphids are small, soft-bodied, pearl-shaped with a pair of cornicles projecting out from the fifth or sixth abdominal segment. Wingless female aphids are yellowish green, gray green or olive green with a white waxy bloom covering the body. The winged females have a dusky green abdomen with dark lateral stripes separating the body segments and dusky wing veins. Males are olive-green to brown in color (TIFP, n.d.-b).

**Life cycle and damage**: Mustard aphids infest the crops right from vegetative stage to pod stage. Both nymph and adults suck the sap from leaves, buds and pods. Curling may occur for infested leaves and at advanced stage plants may wither and die. Plants remain stunted and sooty molds grow on the honey dew excreted by the insects. The infected filed looks sickly and blighted in appearance. Rainy and humid weather help in accelerating the

**Economic and action thresholds:** The economic threshold level for mustard aphid for

**Control**: planting tolerant or resistant varieties can reduce population build up. *Cocciniella septempunctata* (L.), *Menochilus sexmaculata* (F.), *H. variegata*, *Cheilomenes vicina* (Mulsant), *Sphaerophoria* spp., *Eristallis* spp., *Metasyrphis* spp., *Xanthogramma* spp. and *Syrphus* spp. are

**5.2** *Lipaphis erysimi* **(Kalt) (Homoptera: Aphididae)** 

growth of insects. They have four nymphal instars (TIFP, n.d.-b).

most efficient predators of the mustard aphid (TIFP, n.d.-b).

**Monitoring:** install yellow stick trap to monitor aphid population (TIFP, n.d.-b).

different regions of India is 23–25 aphids per plant (Chattopadhyay et al., 2005).

#### **5.3** *Myzus persicae* **(Sulzer) and** *Brevicoryne brassicae* **(Linnaeus) (Homoptera: Aphididae)**

**Identification:** They are known as peach potato aphid and cabbage aphid, respectively. The eggs are usually elliptical in shape, initially yellow or green, but soon turn black. Nymphs look like to the viviparous adults. Winged aphids of *M. persicae* have a black head and thorax, and a yellowish green abdomen with a large dark patch dorsally. They measure 1.8-2.1 mm in length. The wingless forms are yellowish or greenish in color and about 1.7-2.0 mm long. They may have a medial and lateral green stripes. The cornicles are moderately long, unevenly swollen along their length, and match the body in color. The appendages are pale (Capinera, 2005). Wingless females of *B. brassicae* are about 2.1- 2.6 mm long oval shaped and the posterior end of the body tapers greatly. The pale green body is usually covered by white waxy powder. Underneath the wax there are eight dark brown or black spots located on the upper abdominal surface. They increase in size toward the posterior end. Winged females are a little smaller than the wingless forms and they are not covered with waxy powder. The head and thorax are dark brown to black. The yellowish green abdomen is with two dark spots on the dorsal anterior abdominal segments. Antennae are dark brown. Wings are short and stout with prominent veins (Kessing & Mau, 1991).

**Life cycle and damage**: Eggs of *M. persicae* are deposited on *Prunus* spp. trees, where they overwinter. After several generations when the aphid densities increased the winged forms produced and disperse to the summer hosts. However, *B. brassicae* is restricted to herbaceous Brassicaceae throughout its life cycle. They lay their eggs on the stems and leaves of cruciferous crops that remain in the field through the winter. Both of these aphids overwinter in the egg stage. Generally aphids feed by sucking sap; infested seedlings may become stunted and distorted. Continued feeding on mature plants causes wilting, yellowing and general stunting of the plants. For peach potato aphid only very heavy infestations cause direct damage. Numbers may increase after serious outbreaks of insecticide-resistant aphids on potatoes. Peach potato aphids transmit the beet western yellow virus, which causes temporary reddening of infected plants in spring. In the case of cabbage aphid, spring rape can become severely infested after mild winters and allow infestations on winter rape to increase to damaging levels. The cabbage aphid is a vector of 23 virus diseases of Brassicaceae. It carries cauliflower mosaic virus. Also, turnip mosaic virus is carried by cabbage aphid and green peach aphid (Jellis, 2003).

**Monitoring:** monitor weekly from flowering to grain fill of the crop. At least four sampling points of random 20 plants should be spread over the field and estimate the number of aphids per plant.Also, yellow traps can use for monitoring aphids (Bailey, 2007).

**Economic and action thresholds:** *B. brassicae* action threshold is if over 13% of winter rape plants or over 4% of spring rape plants are infested before petal fall (Jellis, 2003). The threshold for *M. persicae* is correspondingly lower, at 25% of plants infested (Bailey, 2007).

**Control**: The parasitoid, *Diaeretiella rapae* (McIntosh) normally provides good control of cabbage aphid. Insecticide resistance has been observed for *M. persicae;* so expert advice on alternative insecticides should prepare. In the case of *B. brassicae* using a higher rate of pirimicarb plus added wetter is recommended (Jellis, 2003).

Oilseed Pests 157

*nigripes* (Fabricius)*,* (turnip flea beetles) attack crops in autumn and spring; and *Phyllotreta* 

**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

**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

**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).

**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

**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

**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).

*nemorum* (L.) (large striped flea beetle) which attacks crops in spring (Jellis, 2003).

level should be determined for estimating time of management (Alford, 2003)

the field or over 50% petioles damaged (Jellis, 2003; Knodel & Olson, 2002).

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

3 mm long and have a head capsule and six legs (Jellis, 2003).

crops are much more vulnerable than winter crops (Jellis, 2003).
