A new protein discovered in the venom of Australian tarantulas can also kill insect pests that consume the venom orally. The protein known as orally active insecticidal peptide-1 (OAIP-1) was found to be highly toxic to insects that consumed it, with a similar efficacy to the neonicotinoid insecticide imidacloprid. In particular, the protein was found to be highly toxic to the cotton bollworm, Helicoverpa zea.
Many spider species have evolved insecticidal toxins in their venom, which they inject into the prey through their fangs. Consequently it has often been presumed that the venom would not be toxic when ingested orally by insects pests, and therefore would not be suitable for use as an insecticide. Conversely, the scientists in this study discovered it is possible to isolate spider venom peptides with high levels of oral insecticidal activity. The team used the venom from Selenotypus plumipes which is a large tarantula native to Australia which despite its large size is not harmful to humans.
Cotton topping has been reported to reduce bollworm infestations without negatively affecting cotton yields. Scientists in Mali looked at three bollworm species, which are responsible for the majority of cotton yield losses in sub-Saharan areas of Africa, where topping is no longer employed.
Cotton topping is an agricultural technique in which the shoot tips of cotton plants are cut off by farmers. It has been used in some sub-Saharan Africa regions to increase crop yields, but has not previously been studied in the context of reducing crop pests.
One species of concern is the cotton bollworm, Helicoverpa armigera, which is a pest of major importance in most areas where it occurs, damaging a wide variety of crops including cotton. The distribution map on Plantwise.org includes nearly 600 distribution points. The presence of two to three larvae on a cotton plant is enough to destroy all the bolls (the protective capsule that cotton grows in) within 15 days. It can be controlled with pesticides as long as they are applied in the early stages of their growth.