Editors: W.T. Wilsey, C.R. Weeden and A.M. Shelton

Diamondback Moth (Plutella xylostella) - Life Cycle
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Adults:
Adults are slender, very small, 1/3 inch (8mm) long, grayish-brown moths with folded wings flaring outward and upward at their posterior ends. The folded forewings of the male form a row of three diamond-shaped yellow spots where they meet along the middle of the back. 

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Eggs:
Diamondback moth eggs are small round, yellowish-white and laid singly or in groups of two or three on the underside of lower leaves or on the lower stalks. Egg hatch occurs in 5 to 10 days depending on the prevailing temperatures.

Larvae:
Diamondback larvae pass through four instars (growth stages). First instars, upon hatching, begin mining within the leaf tissue, whereas later instars feed on heart leaves of young plants and/or the underside of the leaf surfaces of more mature plants.

Mature larvae are 1/3 inch (8mm) long, pale greenish-yellow, and pointed at both ends. Diamondback larvae can be distinguished from other young pest species by their habit of actively wriggling or dropping from the leaf on a silken thread when disturbed. Larval development is completed within 10 days to 4 weeks depending on temperature.

Pupae:
The pupa develops within a delicate, loosely spun, open lacework cocoon that is attached to the leaves and stems of the plant. Adults emerge in 7 to 15 days.


Damage inflicted by diamondback moth on cabbage and crucifers


Some information on this page taken from Insects of Crucifers: Factsheet number 102GFS751.20 authored by J. T. Andaloro, and P. B. Baker.

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Maintained by Jason D. Plate. Last updated Mar. 8th, 2007.