Influência dos tricomas glandulares da batateira Solanum berthaultii Hawkes na ação de Aphidius colemani Viereck, 1912 (Hymenoptera: Aphidiidae) e de Scymnus (Pullus) argentinicus (Weise, 1906) (Coleoptera: Coccinellidae) sobre o pulgão Myzus persicae (Sulzer, 1776) (Homoptera: Aphididae)

Abstract

The objetive of this research was to evaluate the influence of glandular trichomes of the potato plant Solanum berthaultii on searching time, mortality and parasitism rate of Aphidius colemani on Myzus persicae and to determine the effect of glandular trichomes on the larval development, mortality and prey capacity ofScymnus (Pullus) argentinicus on M. persicae.This research was conducted in the laboratory of Biological Control (25 ±1 C°, 70 ± 10 % R.H. and 12 hours of photoperiod) at the Federal University of Lavras, Minas Gerais State, BraziL A. colemani, was tested on two species ofpotato (S. berthaultii and S. tuberosum) at three densities of M. pesicae. The searching time was tested with densities ofof 5, 10 and 20 nymphs of2a1 and 3"1 instar of M. persicae/leaf. The parashoid mortality and parasitism rate of A. colemani was set at densities of20, 40 and 80 nymphs/plant. The infiuence ofthe glandular trichomes on mortality and prey capacityofS. (Pullus) argentinicus was determined with 40 larvae recentlyhatched. The infiuence ofthe glandular trichomes on mortality and prey capacityof5. (Pullus) argentinicus on M. persicae was conducted on two species ofpotato (S. berthaultii and S. tuberosum) x five (1^, 2°*, 3ld'4th instars and adult ofS. (Pullus) argentinicus). The searching time ofA. colemani on M. persicae was 273 seconds in S. tuberosum, though in S. berthaultii there wasn't aproximation of A. colemani on M. persicae in 45 minutes of observation after 72 h. It was observed higher mortality of A. colemani on S. berthaultii plants (10, 75 and 88.25 %) than S. tuberosum (37.50, 20.75 and 25%). The rate of parasitism ofA. colemani on M. persicae was higher on S. tuberosum (55, 60 and 66.88%) than S. berthaultii (6.65, 6.68 and 3.33%) for 20, 40 and 80 nymphs on 2nd and 3rf ofM. persicae/ptent respectively. Interaction between A. colemani and resistant potato plant (S. berthaultii) for the reduction ofthe number ofnymphs ofM. persicae was not found, beingof60.63% in S. tuberosum (for the action ofA. colemani) and of39.74 % in S. berthaultii (5.55 % for the action ofA. colemani and 34.19% for the effect ofthe glandular trichomes). The results ofthe test with S. (Pullus) argentinicus shown that the glandular trichomes interrupted the larval development, for the higher mortality in the first instar (89%), by the action ofthe glandular trichomes ofS. berthaultii. The time for larval development ofS. (Pullus) argentinicus was similar in both species: S. berthaultii (7.5 days) and S. tuberosum (7.8 days), though that predation was lower in S. berthaultii (14.10 nymphs) in relation S. tuberosum (28 nymphs). The larval mortality ofS. (Pullus) argentinicus was high (Ia, TA, and 3rfinstar) in S. berthaultii, but in S. tuberosum there was no mortality in 24 and 48 hours periods. The prey capacity ofS. (Pullus) argentinicus was signicantly higher in S. tuberosum than on S. berthaultii for ali instars and adult stages. There wasn't interaction between resistant potato plant S. berthaultii andS. (Pullus) argentinicus inthe actionon M. persicae.