Agricultural pesticides are not very popular these days. Not so long ago, these chemicals were hailed as the best weapon in a farmer’s arsenal. And the possibility of better harvests and less crop waste was a thrilling advancement as the world’s population grew and more mouths needed food. Compare this to today’s perspective, where parents worry about their children’s pesticide loads and the demand for organic products is skyrocketing.

Pesticides are used to kill off insects and other species that damage crops. These organisms can wreak havoc on a field, leaving the farmer with cost of production and no product. In place of chemical treatments, research is turning to other possibilities, such as natural predators, mixed crops, and so on.

Part of the solution lies in understanding the threat - namely, the crop pest itself. One study published this week in Science, a scientific journal, has examined the whitefly. Despite its rather nondescript name, the whitefly is an extremely invasive pest, particularly a group known as Bemisia tabaci Biotype B. This population has spread across many countries, often through infestations on ornamental plants such as poinsettias. China has been battling this pest over the past decade. Tomatoes, grapes, cotton and tobacco are some of the hardest-hit crops, but whitefly affects many agricultural plants.

Whiteflies feed on leaves, causing plants to wilt or even die. They secrete honeydew, a sticky material that coats the plant and acts as a substrate for sooty molds. Whiteflies also spread plant viruses. In fact, earlier this year, a study found that plants infected with begomoviruses have faster-growing whitefly populations compared to healthy plants.

Mating turns out to be another part of the whitefly’s success story, especially mate choice. Apparently, females of the invasive Biotype B prefer males of the same group. Biotype B males mate with these females, but they also court native females. The result: native males and females manage to mate less and their population gets swamped by the thriving Biotype Bs.

From an agricultural standpoint, it seems that the whitefly you know best (native types) is preferable to the invasive form (Biotype B). Pesticides have variable success with Biotype B. However, the immature form of the whitefly is eaten by a variety of insects, including lacewings and ladybugs, as well as hosting certain parasites. Better understanding of whitefly, including its life history and behaviour, can pave the way for biological pest control of this devastating pest insect.