Synonyms and other taxonomic changes
Described by Linnaeus.
Identification
Adult: forewing of male dark gray or brown with irregular white band along inner margin; coloring darkest just above white band; forewing paler in female, so contrast with inner margin border less pronounced; hindwing gray; white forewing markings form a "diamond" when moth folds its wings together
(1)Range
Per Capinera: The diamondback moth is probably of European origin but is now found throughout the Americas and in Europe, Southeast Asia, Australia, and New Zealand. It was first observed in North America in 1854, in Illinois, but had spread to Florida and the Rocky Mountains by 1883, and was reported from British Columbia by 1905. In North America, diamondback moth is now recorded everywhere that cabbage is grown. However, it is highly dispersive, and is often found in areas where it cannot successfully overwinter, including most of Canada.
Season
adults fly from March to October; multiple broods
Food
Per Capinera: Only plants in the family Cruciferae. Virtually all cruciferous vegetable crops are eaten, including broccoli, Brussels sprouts, cabbage, Chinese cabbage, cauliflower, collard, kale, kohlrabi, mustard, radish, turnip, and watercress. Not all are equally preferred, however, and collard will usually be chosen by ovipositing moths relative to cabbage. Several cruciferous weeds are important hosts, especially early in the season before cultivated crops are available.
Life Cycle
Per Capinera: Total development time from the egg to pupal stage averages 25 to 30 days, depending on weather, with a range of about 17 to 51 days. The number of generations varies from four in cold climates such as southern Canada to perhaps eight to 12 in the south. Overwintering survival is positively correlated with the abundance of snowfall in northern climates.
Remarks
Per Capinera: Diamondback moth was long considered a relatively insignificant pest. Its impact was overshadowed by such serious defoliators as imported cabbageworm, Pieris rapae (Linnaeus), and cabbage looper, Trichoplusia ni (Hubner). However, in the 1950s the general level of abundance began to increase, and by the 1970s it became troublesome to crucifers in some areas. Insecticide resistance was long suspected to be a component of the problem. This was confirmed in the 1980s as pyrethroid insecticides began to fail, and soon thereafter virtually all insecticides were ineffective. Relaxation of insecticide use, and particularly elimination of pyrethroid use, can return diamondback moth to minor pest status by favoring survival of parasitoids.
See Also
Honeysuckle Moth (
Ypsolopha dentella) has a spur projecting diagonally from the pale forewing strip about two-thirds distance from base, and its forewing tip is hooked
Internet References
diamondback moth - Plutella xylostella (Linnaeus) - Featured Creatures - John L. Capinera, University of Florida
live adult images plus description, foodplants, flight dates (Lynn Scott, Ontario)
live adult images by various photographers (Moth Photographers Group)
