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The female lays 250 eggs during a season and six generations may develop under optimum conditions when the temperature is in the range 15–20 °C. As the number of nematodes increases, symptoms become visible. Onion leaves start to curl, garlic leaves become yellow and die, bulb scales are loosened, and bulb necks become cracked.
The larvae damage bulbs of onions, garlic, chives, shallots, leeks, and flowering plants. The first generation of larvae is the most harmful because it extends over a long period owing to the females' longevity and occurs when the host plants are small. Seedlings of onion and leek can be severely affected as can thinned-out onions and shallots. [3]
In some populations, nearly all onion thrips are female, and males are very rare. [2] The adult onion thrips is some 1 to 1.3 mm (0.04 to 0.05 in) long. The body is some shade of yellow, yellowish-brown or brown; the antennae have seven segments, the wings are well-developed and females have an ovipositor at the tip of the abdomen.
Main article: Human parasite Endoparasites Protozoan organisms Common name of organism or disease Latin name (sorted) Body parts affected Diagnostic specimen Prevalence Source/Transmission (Reservoir/Vector) Granulomatous amoebic encephalitis and Acanthamoeba keratitis (eye infection) Acanthamoeba spp. eye, brain, skin culture worldwide contact lenses cleaned with contaminated tap water ...
Control is by crop rotation (at least 3 years between successive onion crops), use of healthy bulbs for planting (heat treatment has been used to eliminate the pathogen from bulbs), fungicide treatment of the bulbs for planting, and fungicide sprays of the foliage if downy mildew infection is nevertheless observed.
The female is flightless, spending her brief life attached to her cocoon. The female attracts other males via release of a pheromone, the males find the female via the concentration gradient of the released pheromone. The female mates and lays her grey-yellow eggs in large numbers on her fine-meshed cocoon.
Agrotis ipsilon, the dark sword-grass, ipsilon dart, black cutworm, greasy cutworm or floodplain cutworm, is a small noctuid moth found worldwide. [2] The moth gets its scientific name from black markings on its forewings shaped like the letter "Y" or the Greek letter upsilon. [3]
Antennectomized female Heliothis virescens, or those who had their antennae removed, mated with hair-pencil pheromone displaying males less often than those which had been sham-operated, suggesting that C. virescens females are dependent on their antennae to detect these pheromones. If the hair-pencil was surgically removed from the male ...