Management of Late-Season Adults of the Colorado Potato Beetle (Coleoptera: Chrysomelidae) With Entomopathogenic Nematodes

Abstract

The susceptibility of Colorado potato beetle [Leptinotarsa decemlineata (Say), Coleoptera: Chrysomelidae] to entomopathogenic nematodes (Steinernema carpocapsae, ’All’ strain, Nematoda: Heterorhabditae) was tested in the laboratory and the field in 1992 and 1993. Under laboratory conditions, applications of 5.0 × 105S. carpocapsae per square metre to larvae, pupae, and (or) adults resulted in 100% mortality in all experimental groups. Steinernema carpocapsae persisted through the larval–pupal and pupal–adult transitions. A single application of nematodes was sufficient to control the Colorado potato beetle. The following treatments were tested at field sites in New Brunswick and Prince Edward Island: (i) untreated check, (ii) application of nematodes, or (iii) application of insecticides. Straw mulch was either present or absent in each treatment. In 1992 in New Brunswick, nematodes and fenvalerate reduced Colorado potato beetle populations by 31% compared with the untreated check. However, in 1993, differences among treatments were not significant. The results from the field trials in Prince Edward Island were variable; the life expectancy of nematodes is likely shorter in the field than under laboratory conditions. Further investigation into the benefits of repeated applications of nematodes, higher rates, or improvements in application technology are required to achieve consistent control of the Colorado potato beetle.

Entomopathogenic Nematodes (Nematoda: Rhabditida) in Slovenia: From Tabula Rasa to Implementation into Crop Production Systems

“…The results of our study have shown that the Slovenian strain Steinernema feltiae (B30) and the commercial preparation Entonem (S. feltiae) are efficient biological agents for suppressing above-ground insects, particularly larvae stages, of Colorado potato beetles outdoors. Though some previous laboratory studies confirmed efficiency of EPNs also with adult specimens of Colorado potato beetles (Stewart et al, 1998;Trdan et al, 2009), the results of laboratory experiments can be hardly compared with those which are obtained outdoors (Cantelo and Nickle, 1992). The results of our study have shown that the activity of EPNs on younger larvae at high concentrations is similarly fast as with the insecticide thiamethoxam, while the activity of nematodes on older larvae was delayed.…”

“…We should not, however, neglect the important fact that laboratory results are not always comparable with field experiments (Cantelo and Nickle, 1992), since the efficiency EPNs outdoors depends on many other factors and interaction between them. In a similar experiment S. carpocapsae was 100 % efficient in suppressing larvae, pupae and adult specimens of Colorado potato beetles, while it reached only 31 % efficiency when its activity was tested outdoors (Stewart et al, 1998).…”

Activity of four entomopathogenic nematode species against different developmental stages of Colorado potato beetle, Leptinotarsa decemlineata (Coleoptera, Chrysomelidae)

“…But it is also important to note that results from laboratory tests are not always comparable with field testing (Cantelo & Nickle, 1992) as functioning of EPNs in the open is influenced by an extensive list of factors. In one relevant study, the 100 % efficacy rate of S. carpocapsae in controlling Colorado potato beetle adults, pupae and larvae in the laboratory manifested in only a 31 % reduction rate of the pest population when the test was repeated outdoors (Stewart et al, 1998) and a supporting dose of fenvalerate was considered. Some further results from studies of the activity of EPNs on related (Yang et al, 2003) and others species of beetles (Łabanowska et al, 2004) have also shown that these agents could be an effective alternative to insecticides.…”

“…In one of the latest studies (Prishchepa et al, 2000), the efficacy of the Belarus strains of Steinernema feltiae and S. carpocapsae has been proven -and the results of other studies indicate the higher efficacy of S. carpocapsae in comparison with strain HP 88 from the genus Heterorhabditis (Saringer et al, 1996). A study in North America has shown that S. carpocapsae persists in the body of the Colorado potato beetle through both the larval-pupal and pupal-adult transitions (Stewart et al, 1998). This indicates that S. carpocapsae could be more useful for foliar application where the nematodes are unlikely to survive long outside a host due to their sensitivity to environmental factors.…”

Physical Control in Greenhouses and Field Crops

“…The effect on densities and migration were examined and showed that the mulch aided somewhat in reducing the population by enhancing natural enemies, but not in disruption of dispersal (Brust 1994;Hoy et al 1996;Stoner et al 1996). Straw mulch was also used to increase the efficacy of entomopathogenic nematodes against the black vine weevil (Otiorhynchus sulcatus (E); Wilson et al 1999) and the CPB (Stewart et al 1998) by increasing soil moisture. Wheat straw mulch was used to repel Aphis gossypii Glover populations from cotton (Rummel et al 1995).…”