 |
ProCrop |
Life Cycle and Identification of Wheat Midge
ADULTS: The adult midge is very small, fragile orange fly about 1/8 inch long. Two jet black eyes cover much of its brown head. The midge has three pairs of legs which are large relative to the insect's body size. Its single pair of wings are oval shaped, transparent and fringed with fine hairs.
Adult midge emerge from the pupal stage in late June or early July. The females mate almost immediately after they emerge.
During the day, the adult midge stays within the crop canopy where conditions are humid. In the evening or during periods when skies are overcast, the females seek out susceptible plants on which to lay their eggs.
Wheat is susceptible to infestation as the heads begin to emerge from the boot. An average of 40 eggs may be deposited during the lifetime of the female midge which usually lasts less 3 to 5 days
EGGS: Egg laying takes place if wind speeds are less than six mph and air temperature is greater 15 degrees C (59 degrees F). Eggs are laid singly or in clusters of three or four eggs within the florets or in grooves on the florets. The egg stage usually lasts four to seven days.
LARVAE: Upon hatching, the small orange larvae find their way to a developing kernel of grain where they feed on the surface of the seed. Frequently, there are three to four larvae per floret, but occasionally there can be as many as 26 larvae feeding on a single seed.
Larvae feed and develop for about two to three weeks by which time they are about 1/8 inch. The last larval stage or instar is different in form and behavior from those of previous larval growth stages.
If conditions are dry, the larvae do not shed their last larval skin but shrink away
from it and stop developing. In this state, the larvae appear to be enclosed in a
transparent envelope. The larvae can survive in this protective stage for up to two
months. As soon as conditions become moist or wet, the larvae become active. They crawl
off the wheat heads and bury themselves in the soil.
Most of the larvae remain in the top two inches of soil, but some may go as deep as four inches. The larvae then spin round cocoons which are about half the size of a turnip type canola seed (B. campestris) and become dormant. In this state, the larvae may remain for more than 13 years if the climatic condition required for continuation of their development do not occur.
Larval diapause may be broken if larvae are cooled below 10 degrees C (50 degrees F) for 120 days.
For more information see the Insect Guide at http://www.ext.nodak.edu/extpubs/plantsci/pests/e1143w1.htm
Back to Insect - Durum/HRS
Menu
Back to Midge - Durum/HRS Menu
Back to
HRS/Durum
Menu
Back to Main ProCrop Index
