Description, Biology, Life Cycle, Damage, Common Names, Images
- Host plants: garlic, onion, maize, wheat.
- This mite infests the upper regions of garlic, concentrating on shoots and to a certain extent upon bracts. It is present at all instars on the upper surface of leaves, along the main vein. It then migrates to the protective folds of leaves, before reaching the bulbs between the scales, on which it feeds and multiplies, thus causing them to dry up.
- On cereal crops, the mites firstly congregate in the striae of leaves, developing for preference on turgescent cells. The toxic saliva injected by the mite rapidly spreads to the entire leaf. The mite then migrates to the wheat ears, the less compact being the most prone to attack.
- This mite is highly sensitive to dryness and cannot survive for longer than 8 hours at 24°C without nourishment. Its dispersion depends upon temperature, wind and light.
The mite hibernates on wheat and certain Graminacae species. As soon as the temperature rises, it moves to the tip of newly opened leaves whence it migrates to opening foliage and thus reaches the top of the plant.
Each female lays one egg per day. Total fecundity is 3 to 25 eggs, laid along leaf veins. Incubation lasts 3 to 5 days at 9°C, and a complete cycle takes 8 to 10 days under favourable conditions.
- On garlic, infested leaves are stunted, distorted, bent and speckled with yellow, particularly at the edges. The tips of some leaves never unroll, but remain beneath other older leaves, giving the plant an arched appearence. Although a plant may resist mild infestation, it can become deformed in the case of major infestation. This mite is also responsible for the dissemination of a mould which causes the rotting of stored bulbs.
- On cereals, leaves may also be distorted and bent. However, the main damage caused is mottling of grains which considerably reduces their value; this probably resulting from the injection of toxic saliva. Yellow grains are mottled with dark red, and white grains with pink.
This mite transmits wheat streak mosaic virus to all varieties of wheat, thus rendering it one of the most harmful eriophyids.
HYPPZ on line : Species (scientific name), Pests (common names), Glossary, Crops.