1/8 Beware the thrips threat. The onion thrip, Thrips tabaci is considered to be the major insect pest of onions Bulb yield can be reduced up to 30% and the damage is compounded by if thrips infect the crop with Iris yellow spot virus, of which they are the main vector. 
2/8 damage caused by thrips can also provide other pathogens with entry points. Thrips species have wide host ranges, feeding on both broadleaf and grass species. Thrips feed on the leaves of onion plants, causing white or silver lesions. High level infestations cause significant
3/8damage that results in reduced photosynthetic area and the plant's ability to produce photosynthates for the developing bulb is compromised. Infestations that develop during the early stages of bulb formation have the largest impact on bulb size and quality. Infestations later
4/8 in the season are less damaging as onions can tolerate higher populations of thrips when they are closer to harvest. Thrips feeding damage affects the leaf quality of green onions because of the formation of feeding scars. Thrips are found deep in the leaf axils. Adults are
5/8 usually brown coloured and up to 2mm long , with the larvae(instars) between 0.5-1.5mm in length. It is mainly the larvae, instar 1 and Instar 2 stages that cause most damage, although the adults can cause significant damage as well. Thrips thrives when conditions are hot and
6/8 dry. Cool weather slows their development, and heavy rain or overhead irrigation can significantly lower populations in an onion planting. These factors can be incorporated in control measures by planting onions in cooler production areas and using overhead irrigation. When
7/8 levels of infestation become critical with a threshold of roughly 15 larvae found on 1 plant, chemical control has to be considered. Responsible use of chemicals is of utmost importance as Insecticide resistant populations can develop quickly. The rotation of insecticides
8/8 from different classes and sources will prevent the insect developing resistance to the chemical used.
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@BlackfordbyGU @MatiengaMambo @marsdee2014 @MukuvariKaroi @IsabellaMaponga @CynthiaTapera @AgritexS @farmbuzz1
#farming #horticulture #charteseeds
@BlackfordbyGU @MatiengaMambo @marsdee2014 @MukuvariKaroi @IsabellaMaponga @CynthiaTapera @AgritexS @farmbuzz1
