Preference and Predatory Potential of Chrysoperla carnea (Stephens) and Coccinella undecimpunctata Linnaeus on Phenacoccus solenopsis Tinsley: A New Threat to the Egyptian Economic Crops
The predatory potential and preference of Chrysoperla carnea (Stephens) larvae and both larvae and adult females of Coccinella undecimpunctata Linnaeus to the cotton mealybug, Phenacoccus solenopsis Tinsley and cotton aphid, Aphis gossypii Glover were investigated under laboratory conditions at Sakha Agricultural Research Station, Egypt. In no choice trails, 3rd instar larvae of C. carnea were the most voracious feeder comparing to 1st and 2nd instar larvae and consumed 673.3+ 6.38, 2756.3 + 20.10, 326.9 + 5.07 and 115.2 + 3.45 insects of aphid, 1st, 2nd, and 3rd instar nymphs of the mealybug, respectively. Similarly, 4th instar grubs of C. undecimpunctata proved to be the most voracious as compared to the younger instar grubs and devoured 112.4 + 1.63, 546.4 + 3.69, 174.1 + 1.07 and 40.2 + 1.22 individuals of aphid, 1st, 2nd, and 3rd instar nymphs of the mealybug, respectively. First instar nymphs of P. solenopsis were significantly the most consumed prey by both predators in the no choice feeding. Adult females of C. undecimpunctata exhibited more feeding potential than its larval stages on all the studied hosts. In free choice tests, A. gossypii was significantly the most preferred host for both predators comparing to the different instar nymphs of P. solenopsis. When C. carnea and C. undecimpunctata larvae were fed in free choice tests, the durations of their larval stages were significantly shorter than that of no choice feeding. The obtained results suggest that both predators could be successfully used as biological control agents for P. solenopsis management under the Egyptian conditions.
Key words: Preference, predatory potential, Chrysoperla carnea, Coccinella undecimpunctata, Phenacoccus solenopsis, Aphis gossypii.