Conservation Biological Control of Aphids in Potato Fields with Reduced Use of Insecticides in Hokkaido, Japan.

Abstract

Abstract:The possibility of reducing insecticide use for controlling direct sucking damage to potatoes by Aphis gossypii was investigated under field conditions. A laboratory experiment was also conducted to determine the possible cause of resurgence in A. gossypii treated with acephate. The susceptibility of A. gossypii to this insecticide was much lower than that of two other inhabiting aphids (Myzus persicae and Aulacorthum solani) and predators (Harmonia axyridis and Orius minutus), indicating that the resurgence of A. gossypii was probably caused by the elimination of natural enemies and competitors by this insecticide. In the field plot without insecticide application, there was no outbreak of A. gossypii (or other aphid species) observed due to suppression by indigenous predators (ex. ladybirds, lacewings, Orius bugs); e.g., the density of A. gossypii did not exceed 10 insects per compound leaf, and no other insect pests were conspicuous. Consequently, both the tuber yield and the starch value were comparable to those in the insecticide-treated plot. The indigenous predators inhabited the environment around the field over a wide area during the potato-growing season. These findings suggested that there is a possibility of realizing potato cultivation without the application of insecticides.

Control of Aphis gossypii and Myzus persicae (Hemiptera: Aphididae) by a flightless strain of Harmonia axyridis (Coleoptera: Coccinellidae) on green pepper plants in open fields

“…In open fields, indigenous predators play an important role in suppressing aphids (Van Den Berg et al 1997;Wells et al 2001;Ito et al 2005). In the present study, only a small number of mummies and predators of aphids were observed throughout the entire duration of the experiment (Tables 2 and 3).…”

Are carabid beetles suitable biotic indicators of insecticide impact in potato fields?

“…This is extremely different from aphid predators (e.g., ladybirds, lacewings, and Orius bugs) in potato fields, most of which are eradicated in pesticide-treated plots (Ito et al, 2005;Ito and Furukawa, 2009). …”

“…In potato production, aphid control is the main reason for spraying insecticides. In Hokkaido Prefecture, where potato production accounts for nearly 80% of the total production in Japan, farmers apply insecticides as a precaution three or four times on average during the season; however, cultivation without insecticides has the potential to be realized: no outbreaks of pest insects have been observed in experimental plots without insecticides, and both tuber yield and starch value are comparable to those in insecticidetreated plots (Ito et al, 2005;Ito and Furukawa, 2009). The low densities of aphids observed in the insecticide-free fields were likely due to the presence of indigenous predators such as ladybirds, lacewings, and Orius bugs (Ito et al, 2005;Ito and Furukawa, 2009).…”

Effect of integrated pest management practices on tomato production and conservation of natural enemies

“…Cycloneda sanguinea and Eriopis connexa (Germar) showed low tolerance to parathion‐methyl in tomato leaf dip assays (Gusmão et al , 2000). Harmonia axyridis was less tolerant than Aphis gossypi (Glover) (Aphididae) to the organophosphate acephate, which could explain resurgence of A. gossypi (Glover) (Aphididae) in areas where this insecticide was used (Ito et al , 2005). The calendar‐based system had also a negative influence on the population of Trichogrammatidae, which parasitizes eggs of N. elegantalis and has been identified as potential candidate for augmented biological control (Parra & Zucchi, 2004).…”