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CABBAGE WORM

Pieris rapae

 

Description:

Adult: cabbage butterfly, white butterfly, tinged with yellow and having 3 or 4 black spots on it's wings which spread to about it' to nearly 2". It emerges with the coming of warm weather in spring.

Egg: Tiny, bullet shaped, ridged, pale to intense yellow in colour. Eggs usually laid on underside of leaves. Hatch in 7 or more days in spring.

Larva: velvety green caterpillars, each having slender orange stripe dorsally and paler broken stripes laterally. Has 5 pairs of prolegs. Attains length of It' - 12t' long then changes to pupa.

Pupa: Naked~grey, green or tan with angular projections suspended by a silk belt. After a week to 10 days it changes to adult.

There are 2 to 3 generations/year in North latitudes.

CONTROL STAGE DESCRIPTION, MIXTURES & AMOUNTS EFFECT ON PEST
1. Cultural      
2. Physical Adult Protective canopies of light-weight polyethylene to prevent infestation Prevents adult from laying eggs on other cabbage leaves
  Larvae Hand picking  
3. Behavioural Larvae Anti metabolites (e.g.) imidazole with oil in water spray Prevents them from eating
a) Repellants Larvae Southern wood and European wormwood  
  Larvae Sour milk or butter milk skim milk mixed with vinegar - spoon sour milk into centre of cabbage Keeps larvae away
b) Companion plants Larvae Interplanting of mint, sage, rosemary, tansy, catnip, nasturtium, tomatoes and celery Repels the larvae
c) friendly insects bacteria Eggs Trichogramma (wasp) Feeds on egg
  Larvae Yellow jacket hornets Feeds on larvae
  Eggs Braconid wasps Feeds on egg
  Larvae Bacillus thuringiensis (available as wettable dust under names of Thuricide and Biotrol). Be certain that the plants are thoroughly dusted so that larvae will be able to feed on dust. Kill larvae
  Larvae Black birds Eat the larvae
4. Harmless pesticides/ others      
a) sprinkling Larvae Salt and flour mixture : cup of salt and 1 cup of flour. Mix the two and sprinkle over plant. Add 1 oz. Of mixture to the worst affected plants. Larvae eats mixture, bloats up and falls dead.
  Larvae A little salt is sprinkled from shaker-about twice as much as you would use in your food Kills larvae
  Adults Confectionery sugar Desiccant
  Larvae Rye flour - the finer the particles the better the adherence onto the insects body. One pint in enough for all plants in a small garden. Cabbage moth and larvae with dough sticking to their wings, hands and bodies. Sun bakes dough hardens and kills them
b) Sprinkling Larvae Dry material (powdery) road dust, wood ash and cornmeal amount to cover the insect body Block pores prevents respiration
c) Spray Larvae Water - use force but little water to avoid drenching the bed. Use ordinary spray or pressure tank. To wash of younger cabbage worms from plants that would be injured by water.
  Larvae Salt solution : one table spoon or 2 oz. Of salt mixed with a gallon of water To control cabbage worms
  Larvae Hot pepper solution : ground up several pods of hot pepper with equal amount of water, add spoon of soap, powder to make the material adhere Kills larvae
  Larvae White hellebore with milk - the powder from rhizomes and rootlets of the hellebore plant is taken and mixed with milk and sprayed Kills larvae
  Larvae Pyrethrum : ground flowers of certain species of chrysanthemum contain insecticide. It is a preharvest spray because its breaks down rapidly in sunlight or strong artificial light. Rapid "knock down" power
  Larvae Derris - a tuba root Stupefy the larvae
    Rotenone - made up roots of different species of trees especially lonchocerpus from L.Amer. Cube from Peru and timbo from Brazil Slows down the rate of heart action and breathing
  Larvae Ryania dust obtained from L.Amer. Shrub. Ryania native of Trinidad amounts used does not injure plant tissue. It puts larvae in "flaccid paralysis" appetites wane, become incapable of normal activity and stop feeding
  Larvae Nicotine : an antilarval spray. Boil 4 oz. Of non filter tip cigarettes of lb. Of filter tips in a gallon of water for hour. Strain clear brown liquid through nylon stocking Kills larvae.

 

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