Abstract:
To investigate the colonization and dispersal ability of artificially released
Hippodamia variegate in tobacco fields, the hatching, dispersal and retention patterns of
H. variegate at various development stages of the insect in tobacco fields were investigated. The results showed that the hatching rate of
H. variegate egg masses released in the middle of tobacco plants was 83.10%±2.62%, which was significantly higher than that of the egg masses released at the top or bottom of tobacco plants, and not significantly different to the hatching rate of indoor egg masses(the control). The dispersal ability of the newly hatched larvae was weak; only those released on the target tobacco plant were able to spread to the site where the aphids were present. Adult
H. variegate exhibited strong dispersal ability; however, their dwell time on the target tobacco plant was short, with the longest dwell time being 48 hours. Therefore, when using
H. variegate for the control of
Myzus persicae, the middle of the tobacco plant, the back of the leaf and the parts close to aphid damage were optimal locations for releasing
H. variegate eggs. In summary, due to their strong dispersal ability, adult
H. variegate can be released in tobacco fields without fixed-point release and can be attracted to aphids up to 24 plants away (about 15 m).