1. Entomopathogenic Fungi
- Entomopathogenic fungi are fungal pathogens that are capable of killing insect pests. They are natural mortality agents of several insect species and are environmentally safe.
- In cashew, entomopathogenic infection on few pest species like tea mosquito bug, cashew stem and root borer, leaf eating caterpillars and other defoliators have been noticed.
- Specific effective strains of different pathogens can be mass multiplied and used for pest control activities.
Insects with entomopathogenic infection are shown above. From left: Adult TMB, pupa of CSRB and pupa of a defoliator (Euthalia sp.)
Tea mosquito bug
Two fungal pathogens, viz. Aspergillus flavus Johann and A. tamarii (Eurotiales: Trichocomaceae) can cause pathogenic infection to H. antonii.
An entomopathogen, Beauveria bassiana Bals. (Hypocreales: Clavicipitaceae) – IIHR strain isolated from Helopeltis antonii infesting guava was subsequently tested on cashew and found effective under laboratory conditions. However, suitable microclimatic conditions are needed for its field efficacy in cashew plantations.
Cashew stem and root borer
Generally, later stages of CSRB infected by an entomopathogenic fungus namely Metarhizium anisopliae are encountered in few cashew trees, however, the intensity of natural infection is very less.
Mycopathogens like Beauveria bassiana also cause mycosis in grubs of CSRB. The spores could survive for three months under field condition. Mixing of spawn with organic matter like FYM, neem cake and cashew apple can enhance the spore load under the field conditions.
2. Entomopathogenic nematodes
Entomopathogenic nematodes like Steinernema carpocapsae and Heterorhabditis indica are effective against the larvae of cashew stem and root borer. These nematodes could cause mortality of the gubs with in a short time of 6-7 days under laboratory conditions. Studies carried out at ICAR-DCR showed that these nematodes retain their virulence in soil even up to 150 days.