An experiment was conducted to compare the predation efficiency of the coccinellids Harmonia axyridis and Coleomegilla maculata on potato plants, Solanum tuberosum, and on a wild aphid-resistant species, Solanum tarijense. Harmonia axyridis females reduced aphid populations more than C. maculata females. Aphid predation by the predators was reduced on S. tarijense compared to S. tuberosum. Coleomegilla maculata spent less time on S. tarijense than on S. tuberosum. Harmonia axyridis spent the same amount of time on both plant species. The plant species did not affect IGP between larvae. Compared to S. tuberosum, the resistant plant offers M. persicae an enemy-free space against both coccinellid predators., Bruno Fréchette ... [et al.]., and Obsahuje seznam literatury
The impact of the arrival of the exotic coccinellid Harmonia axyridis on the biological control and dispersion of apple mites and aphids, and on the vertical distribution of the established coccinellids Coccinella septempunctata and Coleomegilla maculata have been studied. Assemblages of adults of the three coccinellid species were tested on apple saplings and on apple trees against Aphis citricola and Tetranychus urticae. The presence or substitution of adults of H. axyridis for adults of C. maculata or C. septempunctata did not reduce the predation impact on mite or aphid prey. H. axyridis was a more efficient predator of mites than was C. septempunctata and generated lower prey dispersal from host plants. Substitutions of adults of H. axyridis for those of C. maculata, and in some cases of C. septempunctata, resulted in greater reduction in number of aphids. On apple trees, the three coccinellid species occurred at different heights. Neither C. maculata nor C. septempunctata modified their vertical distribution on apple tree over a 24 hour period in response to the presence of H. axyridis.
Our goal has been to determine the effect of the presence of aphids on voracity (measured as number of prey eaten and biomass consumed) of Coccinella septempunctata L. and Harmonia axyridis Pallas (Coleoptera: Coccinellidae) feeding upon the oblique-banded leafroller, Choristoneura rosaceana (Harris) (Lepidoptera: Tortricidae). For each coccinellid predator, treatments using a single prey species, with either 30 first instar C. rosaceana or 100 third instars Aphis pomi DeGeer (Hemiptera: Aphididae), were compared with two-prey treatments in which the two prey species were present simultaneously. For both predators, the total number of prey killed (total prey species pooled) and the total biomass consumed were significantly higher when both prey were present than in single-prey treatments. The voracity of C. septempunctata on C. rosaceana larvae was not affected by adding A. pomi, whereas that of H. axyridis declined; the voracity of both predators on A. pomi increased when C. rosaceana larvae were added. The preference for the aphids over C. rosaceana was confirmed for both coccinellid species.
The multicolored Asian ladybeetle, Harmonia axyridis (Coleoptera: Coccinellidae), was first reported in southern Canada in 1994. In this study, we examined the status of the ladybeetle in Quebec agroecosystems seven to ten years after its arrival. We integrated the findings from eight independent field studies carried out in pome fruit, grapes, medicinal crops, field corn, sweet corn, sweet pepper, lettuce, and soybean. Nine aphidophagous and 6 coccidophagous coccinellid species were sampled on these crops. Among these aphidophagous species, three invasive (H. axyridis, Coccinella septempunctata and Propylea quatuordecimpunctata) as well as one indigenous species (Coleomegilla maculata lengi) were consistently present. Higher richness was observed in perennial crops, where the 6 coccidophagous coccinellids were almost exclusively present. Higher abundance of aphidophagous coccinellids was observed in field and sweet corn. The multicolored Asian ladybeetle was a dominant species of the coccinellid assemblage in all crops monitored.