Beet PI seen as potential pest control
Researchers have identified a sugar beet proteinase inhibitor (PI) that has potential for the broad-spectrum control of lepidopteran pests. Serine proteases are the dominant digestive enzymes in Lepidoptera. The study assessed the effects of feeding tobacco ( Nicotiana benthamiana) leaves expressing the beet serine PI (BvSTI) to larvae of five lepidopteran tobacco and/or sugar beet pests. In three species, fall armyworms ( Spodoptera frugiperda), beet armyworms ( S exigua) and tobacco hornworms ( Manduca sexta), larvae weighed significantly less than controls fed on normal tobacco leaves. However, larval weights increased compared to controls in tobacco budworms ( Heliothis virescens) and black cutworms ( Agrostis ipsilon). Mortality rates in H virescens were some five times greater than controls. Developmental abnormalities of the pupae and emerging moths were noted in all five species. They are all pests in tobacco, while S frugiperda, S exigua and A epsilon are also pests of sugar beet.