Damage potential and phenology of the Colorado potato beetle [Coleoptera: Chrysomelidae] on potato in southern Alberta

Abstract

The phenology and damage potential of the Colorado potato beetle (Leptinotarsa decemlineata) were studied in the potato producing area in southern Alberta. Experimental plots were established at Lethbridge in 1998, 1999 and 2000, and at Vauxhall in 1998 and 1999. At each site, one plot was protected against the beetle by application of insecticides while the other was "unprotected." Natural potato beetle populations quickly colonized unprotected plots each year. Overwintered adults appeared in plots by mid June with mean densities reaching between 0.3 and 0.6 per plant. Eggs were laid on young plants with mean densities reaching two egg masses per plant by late June. Maximum larval densities reached 9.5 per plant for each of 1st, 2nd and 3rd instars and 14 per plant for 4th instars. Maximum density for newly emerged adults was 57 per plant in mid-July at the 2000 Lethbridge unprotected plot. Defoliation was very low at the beginning of the season but increased sharply when 3rd and 4th instar populations peaked and continued to rise as new adults emerged. Maximum defoliation occurred at the Lethbridge plot in 2000 with 100% defoliation by 10 August. Total yields in all unprotected plots ranged from 10 to 40% lower than in the protected plots. Mean density of overwintering adults within potato plots was 76 beetles m-2 with a maximum of 232 m-2. Mean overwintering mortality was 22% and mean depth of overwintering adults was 12 cm, with 63% of the beetles collected at depths ≤ 10 cm. Our results indicate that the phenology of the beetle is similar to that reported in areas where population buildups were rapid and devastating soon after insecticide resistant populations appeared. Consequently the beetle must be considered as a serious threat to potato production in southern Alberta.

Behavioural responses of the Colorado potato beetle to trichomes and leaf surface chemicals of Solanum tarijense

“…The Colorado potato beetle [ Leptinotarsa decemlineata (Say) (Coleoptera: Chrysomelidae)] is present in the North American, European, and Asian continents (Jolivet, 1991) and is the most important defoliator of the potato crop in North America. Left uncontrolled, the Colorado potato beetle can totally defoliate plants and reduce yield by 40% during a single generation (Noronha et al, 2002). The need to control this insect, its ability to develop resistance to insecticides, and concerns about the impact of insecticides on the environment and human health have triggered more interest in the development of insect-resistant potato cultivars.…”

Acute and sublethal toxicity of novaluron, a novel chitin synthesis inhibitor, to Leptinotarsa decemlineata (Coleoptera: Chrysomelidae)

“…The Colorado potato beetle, Leptinotarsa decemlineata (Say), is the most important insect defoliator of potato worldwide. Left uncontrolled, L decemlineata populations, particularly late‐instar larvae, can quickly defoliate entire potato fields and sharply reduce yields 1, 2. Limited utility of alternative control methods has meant heavy reliance on chemicals to manage L decemlineata , resulting in rapid development of insecticide resistance and exhaustion of all insecticide options in many potato‐growing regions.…”

Effects of Potato Foliage Age and Temperature Regime on Prediapause Colorado Potato Beetle <I>Leptinotarsa decemlineata</I> (Coleoptera: Chrysomelidae)

“…Decreasing photophase and temperature interacting with plant maturity act as cues to induce diapause preparation, which typically involves intense feeding to store metabolic reserves rather than to reproduce (De Wilde 1954, De Wilde et al 1959, De Wilde and Ferket 1967, Hoy et al 1996. Satiated beetles eventually leave the host plant in search of a suitable site where they enter the soil (Voss and Ferro 1990, Noronha and Cloutier 1999, Noronha et al 2002 and dig to a depth of 10 Ð30 cm before coming to rest for diapause (Gibson et al 1925, Hurst 1975, Minder 1976, Ushatinskaya 1978, Weber and Ferro 1993, Noronha and Cloutier 1998.…”