Use of Entomopathogenic Nematodes (Steinernematidae) in Conjunction with Mulches for Control of Overwintering Codling Moth (Lepidoptera: Tortricidae)

Abstract

Mulches were compared to test their utility for enhancing efficacy of entomopathogenic nematodes (EPNs) applied against over-wintering codling moth, Cydia pomonella (L.), larvae. Compared with bare ground, mulches may enhance control by providing cocooning sites for codling moth larvae and a substrate that is easy to treat, maintains moisture, and enhances nematode activity. Steinernema carpocapsae (Weiser) or S. feltiae (Filipjev) were applied at a rate of 2.5 × 109 infective juveniles (IJs)/ha against cocooned sentinel codling moth larvae in cardboard strips followed by 2 h of irrigation in plots that were covered with one of four mulches (clover, shredded paper, grass hay or wood chips) or to bare plots on 29 September 2003. Average mortalities of 97 and 98% were observed in paper-mulched plots treated with S. carpocapsae or S. feltiae IJs, respectively, compared to 80 and 76% mortality in bare plots. Larvicidal activity for S. feltiae against sentinel larvae in cardboard strips that were placed in crevices in the soil was nearly identical in all mulched and bare plots (97–100% mortality), but reduced for S. carpocapsae in wood chip and clover plots (76–79% mortality) relative to paper, grass hay and bare plots (93–97% mortality). A significant portion of sentinel larvae (25 and 14%) that were placed in crevices in the soil in hay- and paper-mulched control plots revealed the natural presence of EPNs (Heterorhabditis sp.). Applications of S. carpocapsae and S. feltiae at a reduced rate of 109 IJs/ha on 20 April 2004, followed by 1 h of irrigation resulted in 13.1 and 7.4% reduction in sentinel larvae in bare plots compared to 36 and 62% in mulched plots, respectively. Applications of S. carpocapsae and S. feltiae at a rate of 2.5 × 109 IJs/ha on 21 September 2004 to bare and wood chip-mulched plots followed by 1 h of irrigation resulted in 21 and 65% reduction in sentinel larvae in bare plots compared to 93 and 85% in mulched plots, respectively. Residual larvicidal activity of EPNs 3 d after applications in treated plots was low, but significant in the nonmulched plots (12–17% mortality) relative to untreated controls (1–2% mortality).

Entomopathogenic Nematode Application Technology

“…The persistence of S. carpocapsae was increased through the use of crop residue to protect the EPNs from environmental extremes (Shapiro, Obrycki, Lewis, Jackson, et al, 1999). Applications of S. carpocapsae and S. feltiae for control of overwintering C. pomonella were greatly enhanced through the addition of wood-chip mulch Lacey, Arthurs, Granatstein, Headrick, and Fritts (2006). Also when investigating control of diapausing C. pomonella using H. zealandica, de Waal, Malan, and Addison (2011) determined differences among various types of mulch with pine wood shavings being most favorable.…”

Organic fruit production in British Columbia

“…These include pheromone-based mating disruption of codling moth via Isomate, codling moth larvae capture using larval aggregation pheromones (Judd and Gardiner 2005) or codling moth population reduction via weekly sprays of granulosis virus (Cossentine and Jensen 2004). Entomopathogenic nematodes can also be used to control overwintering codling moth larvae (Lacey et al 2006a), with efficacy being greater with organic mulch than with bare soil (Lacey et al 2006b). Leafroll caterpillar (Lepidoptera: Tortricidae) larvae can be controlled with the organic microbial pesticide Bacillus thuringiensis Berliner (Bt) (Cossentine et al 2003).…”

Influence of humidity and a surfactant-polymer-formulation on the control potential of the entomopathogenic nematode Steinernema feltiae against diapausing codling moth larvae (Cydia pomonella L.) (Lepidoptera: Tortricidae)

“…Several studies have noted the importance of maintaining moisture for DJs survival and infectivity (Kaya et al 1984;Nachtigall and Dickler 1992;Lacey and Unruh 1998;Unruh and Lacey 2001;Lacey et al 2006a). Lacey et al (2006b) have reported effective control of codling moth when combining irrigation and mulch to extend the survival of DJs. Thus irrigation and mulching the orchard is a possibility to increase EPNs efficacy.…”