Effect of the flowering weed, Euphorbia helioscopia L. (Euphorbiacea) in enhancing the parasitism by the synovigenic parasitoid females of Trissolcus basalis (woll.) (Hymenoptera: Scelionidae) on Nezara viridula (L.) egg masses (Hemiptera: Pentatomidae)

Abstract

Numerous parasitoid species have been proved feeding on flowers nectar of plants that contains sugar, proteins, amino acids, lipids and many other organic and inorganic substances. Consequently, parasitism rates can be increased in the field by feeding on nectar. This investigation aimed to evaluate the effect of the flowering weed, E. helioscopia in raising parasitism rates of Trissolcus bassalis on
Nezara viridula eggs during 2018/ 2019 and 2019/ 2020 at the experimental farm of Sakha Agricultural Research Station, Kafr El- Sheikh Governorate. Results elucidated that seasonal mean of N. viridula egg masses was higher in the third cultivation date (3.91 ± 0.30 and 4.24 ± 1.10) than the first (1.33 ± 0.10 and 1.08 ± 0.10) and second (2.24 ± 0.20 and 2.08 ± 0.20) dates during the first and second seasons, respectively. Further, numbers of T. basalis were higher in the third cultivation date (6.66 ± 2.10 and 4.91 ± 1.20) than the first (1.58 ± 0.10 and 1.41 ± 0.20) and second (4.00 ± 1.10 and 2.58 ± 0.10) dates during the first and second seasons, respectively. On the other side, the parasitized egg masses, emerged parasitoids and parasitism percentages were higher in weedy – plots in the first (4.85 ± 0.10, 23. 90 ± 2.10 and 92.83 ± 6.10) and second (4.47 ± 0.20, 19.94 ± 2.20 and 84.52 ± 5.10) seasons than the weedfree plots (1.56 ± 0.10, 5.33 ± 0.30 and 31.26 ± 4.10) in the two seasons, respectively. The information obtained here might be valuable in increasing our knowledge about the role of flower nectars in conservation of natural enemies, especially synovigenic females of insect parasitoids.