|Crop Knowledge Master|
Brevicoryne brassicae (linnaeus)
Jayma L. Martin Kessing, Educational Specialist
Ronald F.L. Mau, Extension Entomologist
Department of Entomology
This aphid feeds on all cultivated and wild cruciferous plants. Major economic hosts include: broccoli, Brussels sprouts, cauliflower, and head cabbage. It attacks carrot, celery, Chinese broccoli, Chinese cabbage, daikon, radish, kale, rape and most other members of the genus Brassica, however, damage is usually less severe than on cabbage.
A native of Europe, the cabbage aphid is now found in many areas of the world. In the Tropics they are usually confined to higher altitudes. The cabbage aphid was first recorded on Oahu in 1907, and it is now present on all islands.
Colonies of this aphid are found on both lower and upper leaf surfaces and in leaf folds of developing heads, on leaf stalks, and on leaf axles. They are occasionally found on at the soil level.
Aphids feed by sucking sap from their hosts. Infested seedlings may become stunted and distorted. Continued feeding on mature plants causes wilting, yellowing and general stunting of the plants.
The cabbage aphid is a vector of 23 virus diseases of Cruciferae and many diseases of Citrus. Turnip Mosaic Virus is vectored by over 40 aphid species but especially by the cabbage aphid and Myzus persicae (green peach aphid). Both apterae (wingless) and alate (winged) aphids are able to transmit the virus but more transmissions are obtained with apterae forms (Toba, 1962). Transmission is usually in a nonpersistent manner where the virus is taken up into the aphid's mouth while feeding on an infected plant and transferred to a healthy plant during the next feeding or probing of mouth parts. In nonpersistent transmission the virus reproduces in the plant and aphids simply aid in transporting the virus.
Aphids reproduce in two ways. In warm climates like Hawaii, aphid colonies consist completely of females. Reproduction does not involve mating or egg laying. Females give birth to live female nymphs. In temperate climates, aphids reproduce as above during the warmer periods of the year. In the fall, the reproduction changes. Males are produced in response to a decrease in photoperiod or temperature (Blackman and Eastop, 1984). Mating occurs and females lay eggs. Aphids overwinter in the egg stage
Generations are overlapping and continuous throughout the year in Hawaii. The total life cycle represents the period from the birth of the nymph until its death as an adult female. Life cycle duration ranges from 16 - 50 days and is greatly influenced by temperature. The life cycle is shortened at higher temperatures.
Eggs are not produced in Hawaii. In temperate regions this aphid over winters as eggs,
Females give birth to live young that remain on her back until they are large enough to survive on their own. Nymphs are similar in appearance to adults except for their smaller size.
Wingless females are 1/10 inch long and somewhat oval in shape. The posterior end of the body tapers greatly. The pale green body is usually covered by white waxy powder. Underneath the wax there are eight dark brown or black spots located on the upper abdominal surface. They increase in size toward the posterior end.
Winged females, somewhat smaller than the wingless forms, are not covered with waxy powder. The head and thorax are dark brown to black. The yellowish green abdomen is with two dark spots on the dorsal anterior abdominal segments. These spots merge into a dark band across the top of the last abdominal segments. Antennae are dark brown. Wings are short and stout with prominent veins.
It is very important that fields are plowed immediately after harvest. This will reduce spread to other plots. Another useful practice is to rotate plantings with non-host crops.
Naturally occurring parasites and predators are important factors in regulating population densities. Parasitic wasps lay eggs within the aphids. The first sign of parasite activity is the presence of mummified aphids. Syrphid fly maggots and lady beetles are efficient predators of aphids. Syrphid maggots are the more common of the two types of predators. Lacewing larvae are often found among aphid colonies. These larvae are called aphid lions. They are less efficient predators than syrphid maggots and lady beetles.
There are many insecticides that are effective against this aphid. Because of the waxy nature of the pest and crop, care must be taken that sprays provide good wetting of the crop. Proper rates of surfactants in combination with well adjusted spray equipment are important to achieve control with minimum effort.
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Hill, D. S. 1983. Brevicoryne brassicae (L.). pp. 154-155. In Agricultural Insect Pests of the Tropics and Their Control, 2nd Edition. Cambridge University Press, Cambridge, London, New York, New Rochelle, Melbourne, Sydney. 746 pages.
Lockwood, S. 1956. Loose-Leaf Manual of Insect Control. California Department of Agriculture, Bureau of Entomology.
Toba, H. H. 1962. Studies on the Host Range of Watermelon Mosaic Virus in Hawaii. Plant Dis. 46: 409-410.
Metcalf, C. L., and W. P. Flint. 1963. Cabbage and Turnip Aphids. In Destructive and Useful Insects, Their Habits and Control, Fourth Edition (Revised by R.L. Metcalf). pp. 667-668. McGraw-Hill Book Company, New York. 1087 pages.
Zimmerman, E. C. 1948. Brevicoryne brassicae (Linnaeus). pp. 92-93. In Insects of Hawaii, A Manual of the Insects of the Hawaiian Islands, including Enumeration of the Species and Notes on Their Origin, Distribution, Hosts, Parasites, etc. Volume 5: Homoptera, Aphididae. University of Hawaii Press, Honolulu. 464 pages.