Onion thrips are a tiny, oblong insect with feather-like wings. Throughout the life-cycle, onion thrips target the leaves of onion plants. They feed by sucking the liquid from plant tissue, and by doing so can spread nasty diseases. Commercial onion farms are most at risk of significant losses in yield. Infestations are less likely in gardens, but still possible nonetheless.
Heavy infestations can impede plant growth.
Adults: They range from 0.8 - 1.2mm. Colour-wise, these insects can appear yellowish to dark grey. Nymphs: The nymphs look identical to the adults; however, are smaller in size and lack wings. Eggs: They are so tiny, they're almost impossible to see with the naked eye.
New growth is stunted of dies back. Flower discolouration. Loss of colour in leaves. Twisting and distortion of new growth. Foliage may darken and wilt.
Attracting predatory insects such as lacewing can help control thrips in your garden. Provide a refuge for natural garden enemies by incorporating strips of wildflowers or native grasses. Likewise, hanging baskets, climbing plants and log piles make great hiding spots for spiders, predatory bugs and centipedes. Biocontrol is not recommended for commercial growers that may use chemicals to eradicate pests.
Organic insecticides are suggested if you have noticed significant dulling in leaves before late summer.