Life cycle Diamondback moth

1 life cycle

1.1 eggs
1.2 larvae

1.2.1 sex pheromone effect on larvae


1.3 pupa
1.4 adult

life cycle

eggs


eggs

the eggs oval , flattened, measuring 0.44 mm long , 0.26 mm wide. yellow or pale green @ first, darken later. laid singly or in groups of 2 8 eggs in depressions on surface of leaves. females may deposit 300 eggs in total, average production half amount. larvae emerge eggs in 6 7 days.

larvae

the larvae have 4 instars, each average development time of 4 days. larval body form tapers @ both ends. larvae have few short black hairs , colorless in first instar, pale or emerald green black heads in later instars. of 5 pairs of prolegs, 1 protrudes posterior end, forming distinctive v . larvae quite active, , when disturbed, may wriggle violently, move backward, , spin strand of silk dangle.

the feeding habit of first instar leaf mining, although small, mines difficult detect. larvae emerge these mines moult , subsequently feed on lower surface of leaf. chewing results in irregular patches of damage, though upper leaf epidermis left intact. these irregular patches called window panes.

sex pheromone effect on larvae

when female diamondback moths lay eggs, of sex pheromones left behind on leaves. diamondback larvae attracted major component of species-specific pheromone, (z)11-hexadecenal. larvae, sex pheromone foraging indicator, rather mating attractant use find healthy source of food , avoid competition food other species on host plant. after fourth instar, larvae no longer attracted sex pheromone food sources.

pupa


pupa

the yellowish pupae 8 mm long , wrapped in loose silk cocoon. found on lower or outer leaves of food plant, on cauliflower , broccoli, pupation may occur in florets. possible pupa fall off of host plant. pupal stage lasts on average 8 days, ranges 5 fifteen days. before emergence occurs, pupa turn yellowish color browner color.

adult

the lifespan averages 3 4 weeks females, less males. these moths weak fliers, seldom rising more 2 m above ground , not flying long distances. are, however, passive migrants, being transferred wind on long distances. diamondback moths overwinter adults among field debris of cruciferous crops, , active adults may seen during warm periods @ time during winter in temperate areas. not survive cold winters , reinvade colder areas each spring, being carried there wind. moths active @ twilight , @ night, feeding on flowers of cruciferous plants, fly in afternoon during mass outbreaks.