Fungi as epizootic factor in populations of sucking alien insects in north-eastern region of the USA

Mycological analyses of the most economically important alien sucking insects including elongate hemlock scale, Fiorinia externa Ferris (Hemiptera: Diaspididae); European fruit lecanium, Parthenolecanium corni Bouche, (Hemiptera: Coccidae); hemlock woolly adelgid, Adelgid tsugae Annand (Homoptera: Adelgidae) and pear thrips, Taeniothrips inconsequens Uzel (Thysanoptera: Thripidae) were conducted. All fungal cultures isolated from insects in the period of mass mortality were identified based on both traditional morphological characteristics and DNA analyses. The fungi were subdivided into three groups. The first group are included the specialized entomopathogenic species - Mariannaea sp. Myriangium duriaei Mont. & Berk., Myriangium sp., Hirsutella lecaniicola (Jaap) Petch, Hirsutella sp., Metarhiziopsis microspora, Beauveria bassiana (Balsamo-Crivelli) Vuillemin, Lecanicillium muscarium (Petch) Zare & W Gams, L. psalliotae (Treschow) Zare & Gams, Lecanicillum sp. Paecilomyces marquandii (Massee) Hughes, Isaria farinosa (Holmsk.) Fries, Isaria sp. and Colletotrichum acutatum subsp. fioriniae (Marcelino & Gouli) R.G. Shivas & Y.P. Tan. The second group are united the facultative entomopathogens – Rhinocladiella sp., Nectria sp., Botrytis sp., Fusarium sp., Phyalophora sp., Phoma sp.; and the third group - contaminants – Penicillium sp., Cladosporium sp., Scopulariopsis sp., Aspergillus sp., and Trichoderma spp. Local explosive epizootics provoking by specialized fungi – M. duriaei, H. lecaniicola, B. bassiana, Lecanicillium sp. and Mariannaea sp. were registered. Fungi M. microspora, P. marquandii and I. farinosa did not have significant importance as mortality insect factors. Experimental inoculation of insect in laboratory and field conditions using fungi B. bassiana and L. muscarium was resulted to mortality of insects from 45% to 95 % but the pest populations were re-established the high quantity after wintering. The fungi tested in field conditions are ecologically associated with soil and fungal propagules have limited possibility to persist in plant canopy, As a result the single local application of soil-dwelling B. bassiana and L. muscarium fungi cannot result to long-time suppression of insect population which permanently located in plant canopy.