PESTS OF CRUCIFEROUS
MAJOR PESTS
1. Diamond Back Moth
2. Leaf Webber
3. Cabbage Semilooper
4. Cabbage Butterfly
5. Cabbage Borer
6. Mustard Sawfly
7. Cabbage Aphid
8. Cabbage Flea Beetle
1. Diamond back moth: Plutella xylostella (L.) (Plutellidae: Lepidoptera)
Distribution and status: World - wide
Host range: Serious past of Cabbage and cauliflower, but also feeds on other crucifers and solanaceous plants.
Damage symptoms
First instar larvae mine epidermal surface of leaves producing typical white patches. Larvae, second instar onwards feed externally making holes on the leaves and soil them with excreta. Heavy infestations leave little more than the leaf veins.
Distribution and status: World - wide
Host range: Serious past of Cabbage and cauliflower, but also feeds on other crucifers and solanaceous plants.
Damage symptoms
First instar larvae mine epidermal surface of leaves producing typical white patches. Larvae, second instar onwards feed externally making holes on the leaves and soil them with excreta. Heavy infestations leave little more than the leaf veins.
ETL: 20 larvae/l0 plants
Bionomics
Yellowish, pinhead sized eggs are laid singly or in batches of 2-40 on the underside of leaves. A female may lay 18-356 eggs in her life time. Egg period 2 - 9 days. Larva: 8-12 mm long, pale yellowish green in color, pointed at both the ends with fine erect black hairs scattered over the body. Larval period 8 -16 days. Pupa is a barrel shaped silken cocoon which is open at both the ends and is attaché d to the leaf surface. Pupal period 4-5 days. Adult: Small, greyish brown having pale whitish narrow wings with inner margins yellow. Three pale whitish triangular markings on hind margins of each forewing are prominent. At rest, a dorsal median patch of three diamond shaped yellowish white spots clearly visible by joining both forewings. Hind wings have a fringe of long hairs. Adult moth may live for about 20 days. Total life cycle is completed in 15-18 days. There are several generations in ayear.
Bionomics
Yellowish, pinhead sized eggs are laid singly or in batches of 2-40 on the underside of leaves. A female may lay 18-356 eggs in her life time. Egg period 2 - 9 days. Larva: 8-12 mm long, pale yellowish green in color, pointed at both the ends with fine erect black hairs scattered over the body. Larval period 8 -16 days. Pupa is a barrel shaped silken cocoon which is open at both the ends and is attaché d to the leaf surface. Pupal period 4-5 days. Adult: Small, greyish brown having pale whitish narrow wings with inner margins yellow. Three pale whitish triangular markings on hind margins of each forewing are prominent. At rest, a dorsal median patch of three diamond shaped yellowish white spots clearly visible by joining both forewings. Hind wings have a fringe of long hairs. Adult moth may live for about 20 days. Total life cycle is completed in 15-18 days. There are several generations in ayear.
Management
- Grow mustard as trap crop. Raise 2 rows of mustard for every 25 rows of cabbage. Sow first mustard crop 15 days prior to cabbage planting or plant 20 days old mustard seedling at the time of cabbage planting. Plant 35 days old cabbage seedlings.
- Install pheromone trap to monitor DBM adults @ 5 /ha and 25/ha for mass trapping
- Apply Bacillus thuringiensis formulation @1 g/L or NSKE 4% spray. Alternate Bt. sero types kurstaki (B.t.k.)and aizawal (B.t.a.)
- Reduce insects colonising on mustard to prevent defoliation of the entire plant by applying dichlorovas 350 at 10 or 15 days interval starting from 15 days after sowing.
- Conserve larval parasitoids viz., Cotesia plutellae in plains and Diadegma semiclausum in hills. Release 40,000 adults / ac, five times @ 8,000 adults/release commencing from 20 days after planting. Also encourage other parasitoids like Apanteles sicarius, Tetrastychus sokolowski (larval) Diadrumus collaris (larval pupal) and Brachymeria excarinata (pupal parasitoids)
- Depending upon the pest intensity, spray any of the following insecticide with 500 -1000 L water/ha primordial or head initiation stage. Mix teepol or sandovit 0.5 ml/Lt of water whenever sprays are made
- Note: Primordial formation takes place between 17 and 25 days after planting, depending on variety.
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2. Leaf webber: Crocidolomia binotalis (Pyraustidae : Lepidoptera)
Distribution and status: Regular pest of minor status but occasionally reach serious proportions
Host range: Cabbage, radish, mustard and other cruciferous plants.
Damage symptoms
| Young larva feeds gregariously on leaves, later webs together the leaves and feeds. Due to gregarious feeding, rotting of cabbage heads and cauliflower curds are common. Regular pest of minor status but occasionally turn to serious proportions. |
Bionomics
Female moth lays 40-100 eggs on underside of the leaves. Egg period 5-15 days. Larva: with red head, brown longitudinal stripes and rows of tubercles on its pale violet body. Larval period 24-50 days. Pupates in soil, pupa is an earthen cocoon. Pupal period 14-40 days. Adult: Small pale brown with forewing having distinct wavy lines and prominent wavy spots. Hind wings semi-hyaline. Life cycle is completed in 43-82 days. More than one generation may be completed in the season.
Female moth lays 40-100 eggs on underside of the leaves. Egg period 5-15 days. Larva: with red head, brown longitudinal stripes and rows of tubercles on its pale violet body. Larval period 24-50 days. Pupates in soil, pupa is an earthen cocoon. Pupal period 14-40 days. Adult: Small pale brown with forewing having distinct wavy lines and prominent wavy spots. Hind wings semi-hyaline. Life cycle is completed in 43-82 days. More than one generation may be completed in the season.
Management
- Spray phosalone 50 EC 1.0 L, fenvalerate 20 EC or cypermethrin 10 EC or deltamethrin 28 EC 250 ml, cartap hydrochloride 50 SP 500 ml, spinosad 45 SC 125 ml/ha or azadirachtin 0.03% 2.5-5.0 L/ha. Do not repeat the insecticides with similar mode of action.
- The pest is regulated by two larval parasitoids viz., Microbracon mellus and Apanteles crocidolmiae
3. Cabbage semilooper: Tircihoplusia ni (Noctuidae: Lepidoptera)
Distribution and status: USA, India and Sri Lanka
Host range: Cabbage, tomato and other cruciferous vegetables.
Damage symptoms
Caterpillars start scrapping and feeding on the leaves initially and later defoliate entire plant leaving midribs and main veins. More damage is evidenced in nurseries than in main field.
Bionomics
E ggs are greenish white, spherical and sculptured and are laid singly on ventral surface of leaves. Adults are stout moths. Head and thorax grey in colour, while abdomen is white with basal tuft of hairs. Pupation takes place in thintransparent cocoons on ventral surface of leaves. Life cycle occupies on month.
E ggs are greenish white, spherical and sculptured and are laid singly on ventral surface of leaves. Adults are stout moths. Head and thorax grey in colour, while abdomen is white with basal tuft of hairs. Pupation takes place in thintransparent cocoons on ventral surface of leaves. Life cycle occupies on month.
Hand pick and destroy caterpillarsManagement
- Use light trap to attract and kill adults
- Spray quinolphos 0.5% or endosulfan 0.1 % or malathion 0.1 %
4. Mustard Sawfly: Athalia lugens (Tenthredinidae: Hymenoptera)
Distribution and status: Widely distributed in Indonesia, Formosa, Myanmar and the Indian Sub-continent.
Host range: Mustard, toria (Brassica campestris), rapeseed, cabbage, cauliflower, knol-khol, turnip, radish, etc
Distribution and status: Widely distributed in Indonesia, Formosa, Myanmar and the Indian Sub-continent.
Host range: Mustard, toria (Brassica campestris), rapeseed, cabbage, cauliflower, knol-khol, turnip, radish, etc
Bionomics
Dark green larvae have 8 pairs of abdominal prolegs. There are five black stripes on the back, and the body has a wrinkled appearance. A full-grown larva measures 16-18 mm in length. The adults are small orange yellow insects with black markings on the body and have smoky wings with black veins. The mustard sawfly breeds from October to March and undergoes pupal diapause during summer. The adults emerge from these cocoons early in October. They live for 2-8 days and lay 30-35 eggs singly, in slits made with saw like ovipositors along the underside of the leaf margins. Egg period is 4-8 days and the larvae feed exposed in groups of 3-6 on the leaves during morning and evening. They remain hidden during the day time and, when disturbed, fall to the ground and feign death. There are 7 instars with a larval period of 16-35 days. Pupation is in water proof oval cocoons in soil and the pupal period is 11-31 clays. Lifecycle is completed in 31-34 days. It completes 2-3 generations from October to March.
Dark green larvae have 8 pairs of abdominal prolegs. There are five black stripes on the back, and the body has a wrinkled appearance. A full-grown larva measures 16-18 mm in length. The adults are small orange yellow insects with black markings on the body and have smoky wings with black veins. The mustard sawfly breeds from October to March and undergoes pupal diapause during summer. The adults emerge from these cocoons early in October. They live for 2-8 days and lay 30-35 eggs singly, in slits made with saw like ovipositors along the underside of the leaf margins. Egg period is 4-8 days and the larvae feed exposed in groups of 3-6 on the leaves during morning and evening. They remain hidden during the day time and, when disturbed, fall to the ground and feign death. There are 7 instars with a larval period of 16-35 days. Pupation is in water proof oval cocoons in soil and the pupal period is 11-31 clays. Lifecycle is completed in 31-34 days. It completes 2-3 generations from October to March.
Damage symptoms
The grubs alone are destructive. They bite holes into leaves preferring the young growth and skeletonize the leaves completely. Sometimes, even the epidermis of the shoot is eaten up. Although the seedlings succumb; the older plants, when attacked, do not bear seed.
Management
- Give first irrigation 3-4 weeks after sowing as it reduces the bug population significantly. (ii) Spray 1.0 L of malathion 50 EC or 625 ml of endosulfan 35 EC or quinalphos 25 EC in 500-600 L of water per ha once in October and again in March-April.
- Conserve larval parasitoid Perilissus cingulator Morby (Ichneumonidae) and the bacterium, Serratia marcescens Bizio (Enterobacteriaceae)
