Entomopathogenic fungal species from the genera Beauveria, Metarhizium and Lecanicillium are important components in biological control of insect pests. However, temperature, humidity and UV radiation are among the important abiotic factors, which limit their effective usage. In this study, four local isolates of Metarhizium were isolated from different crop rhiospheres of Telangana and Andhra Pradesh states of India, identified and tested for their temperature tolerance in terms of radial growth, conidial yield per 10 mm disc and rate of conidial germination at different incubation temperatures. The results revealed that strains LaMa1 and MaAICRP performed well in terms of radial growth, conidial yield and rate of conidial germination, even at 35°C temperature. The role of such temperature tolerant strains in agriculture is discussed.

Many Entompathgenic fungal species are of agricultural importance as safe alternatives for chemical insecticides in controlling the various insect pests of crops. pH is one of the abiotic factors influencing the activity of these fungi in both laboratory survival and field efficacy. The effect of pH of the media on the biomass growth of seven locally isolated Entomopathogenic fungal isolates was evaluated in the present study. The isolates in general had a wide pH range for their growth but had maximum biomass at low pH of 4 or 5 and least biomass growth at higher basic pH. Variations in growth among isolates were also noticed. The importance of our findings was discussed in the light of the agricultural as well as industrial applications of these fungi.

The polyphagous insect pest Spodoptera litura is known to cause huge losses to agriculture all over the world. Its increasing resistance to chemical insecticides necessitates the use of biological options such as Entomopathogenic fungi. Strains of Entomopathogenic fungi, Beauveria bassiana, Metarhizium anisopliae and Lecanicillium lecanii are known to control the incidence of the pest. Laboratory bioassay was conducted to evaluate the effect of different local isolates of M. anisopliae and L. lecanii on the growth and development of S. litura. Results indicate that the susceptibility of the insect pest depends on various factors like the fungal isolate, dosage of the infective propagule, age of the insect larvae and the developmental stage tested. Among the isolates studied, M. anisopliae isolate PaCo4 was found to be most virulent on S. litura neonates and the isolate ArCo3, the least virulent. In a subsequent study on the 3 rd instar larvae of insect pest, the isolates were found to prolong the larval duration, lower the pupation but the pupal period remained unchanged. A lowered adult emergence and longevity was also observed. Further study of the field efficacy of the Entomopathogenic fungal isolates are needed so that they can be successfully used for controlling the pest on the field.