Pengaruh lama penyimpanan berbagai formulasi cendawan entomopatogen Lecanicillium lecanii terhadap telur hama penghisap polong kedelai Riptortus linearis L. (Hemiptera: Alydidae)

Abstract

The entomopathogenic fungi Lecanicillium lecanii is currently being developed as mycoinsecticide to control the soybean pod sucking bug Riptortus linearis. In the field, without treated in formulation, this bioinsecticide is often unstable. To maintain the viability and infectivity, the fungi must be formulated by adding certain additives. The aim of the research is to study the viability and infectivity of the fungi after storage in several formulations. The fungi were mixed with (1) talcum powder (2) sweet potato powder (3) cassava powder (4) rice powder (5) corn powder (6) molasses (7) peanut oil (8) soybean oil as treatment and (9) water as control, and stored in the room condition. The viability of the conidia as indicated by germination in water after 10 hours, the growth of fungal colony in 4 to 7 days after being inoculated on PDA media, and infectivity to R. linearis eggs were observed each month during 11 month. The experiment was set in completely randomized design with three replicates. The results show that, the viability and the infectivity of the fungi in all formulations decreased along the storage. On the 11th month of storage the viability decreased to 65% (peanut oil, the lowest) and 87% (cassava powder, the highest). Similarly, the infectivity of the fungi decreased as well, to 47% (talcum powder, the lowest) and 76 % (molasses and cassava powder, the highest).