The shot hole borer (Ambrosia beetle): Deciphering component in wilt complex as an emerging issue in pomegranate-A review

Abstract

Ambrosia i.e. shot hole borer beetles are beetles of the weevil subfamilies Scolytinae and Platypodinae (Coleoptera, Curculionidae), which live in nutritional symbiosis with ambrosia fungi. The beetles excavate tunnels in preferably wilted dead, stressed plants and little bits in healthy trees in which they cultivate fungal gardensas their sole source of nutrition. The shot hole borer, Xyleborus fornicatus severely affected pomegranate as this pest occurs sporadically in Ahmednagar. Life cycle from egg emergence to adult life of this pest was completed in 34 days with 13:1 female to male ratio. The symbiotic fungus Fusarium euwallaceae is associated with Euwalla ceae fornicatus causing branch dieback once introduced. Beetle play key role in the mechanical transmission of wilt pathogens. Because of haplodiploidy nature there is no need to find mates, brother-sister mating increases the chances of colonization and therefore, one or a few individuals are sufficient to establish a new population. As deciphering component, the wilt incidence reported from 0 to 46.3 per cent of survey report in Bagalkote followed by Belgavi in Karnataka and stated that the in festation of shot hole borer alone was not noticed. Furthermore, association of shot hole borer and nematode results in higher per cent disease incidence. Maintaining healthy trees by reducing physiological stress is the first recommendation for long term control. If growers maintain optimal condition the ubiquitous amborsia beetle will be in consequential. Pasting of geru with and drenching of emamectin benzoate at 2 g + propiconazole 1 ml per litre water in infested plant will be effective remedy for the management of pest with symbiotic fungal inoculum.