Elevated humidities for control of chrysanthemum pests with Verticillium lecanii

Abstract

Integrated pest control on chrysanthemum is now a possibility. Verticillium lecanii (Zimm.) Viegas is one of the key components as, under the right conditions, it will provide good control of pests such as aphids, thrips and whitefly. High humidity for a number of nights per week is critical for reliable pest control with this fungal pathogen. These conditions can be easily and safely obtained by fogging water over the crop at night. Four consecutive nights of high humidity per week or a cycle of two nights of high humidity and two nights ambient have given excellent pest control with no adverse effect to the crop.

Comparative efficacy assessment of fungi, nematodes and insecticides to control western corn rootworm larvae in maize

“…These factors may also be the reason that both the fungus and the nematode failed once in field 1 of this study. Such failure may be attributed to the comparatively small amount of rainfall in 2006, which may have negatively influenced the fungus (Milner and Lutton 1986;Helyer et al 1992) and the nematode (Ellsbury et al 1996;Portillo-Aguilar et al 1999). However, on average across fields and years, the nematode achieved about 60% efficacy at reducing D. v. virgifera emergence, which is comparable to studies with this nematode in the USA and to the efficacy of insecticides (Jackson 1996;Andersch and Schwarz 2003).…”

“…Occasional failures of fungi or nematodes are usually explained by the use of species or strains that are not adapted to the host or to local conditions (Jackson 1995;Shapiro-Ilan et al 2002), by soil aridity and soil texture (Ellsbury et al 1996;Kessler et al 2003;Koppenhöfer and Fuzy 2006) or by the lack of alternative hosts (Brust 1991;Susurluk 2005). Moreover, fungi and nematodes often require high soil moisture (Milner and Lutton 1986;Helyer et al 1992;Fargues and Luz 1998;Butt 2002;Jaronski 2008) and are sensitive to UV radiation (Ferron 1978;Burges 1981;Butt 2002). Occasional failures of soil insecticides, if not caused by resistances, are usually explained by the adsorption of insecticides to organic soil particles (Felsot and Lew 1989), chemical volatilisation and degradation at high soil temperatures (Getzin and Shanks 1970), surface runoff or leaching during heavy rainfalls (Gorder et al 1982) or biodegradation (Felsot et al 1982;Harris et al 1988;Felsot and Lew 1989).…”

Formulation of Mycoinsecticides

“…For example, modern thermal screens not only raised temperature but also humidity (N. L. Helyer and G. A. Gill, Horticulture Research International, personal communication), as did polythene blackouts to alter daylength (Hall and Burges, 1979;Helyer et al, 1992). When nutrient formulations are used this enables the fungus to grow and sporulate on the leaves, as well as increasing sporulation on cadavers, to continually infect invading pests.…”

Toxicity and feeding deterrence of crude toxin extracts of Lecanicillium (Verticillium) lecanii (Hyphomycetes) against sweet potato whitefly, Bemisia tabaci (Homoptera: Aleyrodidae)

“…However, numerous factors (slow action, poor ovicidal activity, potentially negative interactions with commonly used fungicides, limited shelf life and dependence on favourable environmental conditions) continue to impede the commercial development and/or application of this fungus 8 . Lecanicillium lecanii requires high humidity for germination, for establishment of infection and for sporulation and consequent epizootics,12–14 which commonly facilitates epizootics of plant disease 15. These factors became bottlenecks in the application of L. lecanii in whitefly control 16 .…”