The value of blue-green algae (Spirulina platensis) as a nutritive supplement and toxicant against almond moth [Cadra cautella (Lepidoptera: Pyralidae)]

Blue-green algae, Spirulina platensis is a well-known algal formulation known for its beneficial effects on the growth and development in several types of organisms. Although it is used as a food supplement, it possesses significant toxic effects on growth and development of organisms. This study assessed the positive/negative impacts of S . platensis on almond moth, Cadra cautella (almond moth) that is a serious pest of date fruits and other grains under laboratory conditions. The S . platensis powder were mixed with diet and newly hatched C . cautella larvae were fed. The larvae were observed on alternate days to record the data. The diet was changed once a week. The S . platensis proved very good nutrition supplement at lower dose. Whereas, moderate and high mortality was noted for 5 and 10% formulations, respectively. Moreover, larval span was significantly altered by different formulations and lower formulation (1%) resulted in shorter larval period compared to the rest of the formulations. Although 33% mortality was recorded under 5% S . platensis formulation, however, the larvae which reached to adult stage, copulated, and females laid more eggs. Furthermore, the highest mortality (90%) was observed under 10% S . platensis formulation and a few larvae reached adult stage; thus, no data on pupal period and reproductive traits was recorded for this formulation. These findings proved that S . platensis can be used as nutritional supplement as well as a toxic substance to manage C . cautella in date storage. However, future studies on this are needed to reach concrete conclusions.