This work was initiated for the first time to identify parasitoid species associated with the immature stages of Pieris rapae (L.) inhabiting cabbage plantations in Assiut governorate, Upper Egypt during the 2018 and 2019 cabbage growing seasons. Attacking periods and parasitism percentages (PPs) of the identified parasitoid species were calculated. One solitary parasitoid species, Hyposoter ebeninus was found to attack P. rapae larvae in the field 110 days after transplantation. However, one hyperparasitoid species Baryscapus galactopus was recorded as an internal gregarious hyperparasitoid of H. ebeninus. The solitary larval parasitoid H. ebeninus strikes were recorded throughout the last five weeks of the season with a marked decline before harvesting. Although H. ebeninus revealed 42.00% abundance, it presented 21.69% PP on P. rapae larvae during the entire period of study. One solitary, Brachymeria femorata and two gregarious parasitoid species [Pteromalus puparum (L) and Tetrastichus sp. (Haliday) were recorded as P. rapae pupae parasitoids on October, 2 nd . Parasitism peak was recorded on October, 16 th with an average of 56.25%. The first appearance of the gregarious pupal parasitoid P. puparum was recorded on October, 9 th . Four weeks later, the second gregarious parasitoid (Tetrastichus sp.) was recorded on November, 6 th . Both pupal gregarious parasitoid species were found to be active until harvesting. The gregarious parasitoid P. puparum presented high PP (23.73%) as compared with Tetrastichus sp. which exhibited 6.96% PP during the entire period of study. In conclusion, two solitaries, one hyperparasitoid, and two gregarious parasitoid species were identified. Pupal gregarious parasitoid species together reduced P. rapae pupae populations by 30.69%. These parasitoids could be used in the IPM programs for this pest in the future. At the same time, the effect of hyperparsitoides must be taken into consideration.
This work was carried out at the experimental farm of the Faculty of Agriculture, Assiut University during the 2017-2018 and 2018-2019 cabbage growing seasons. Evaluation of the seasonal abundance of the cabbage aphid Brevicoryne brassicae L in cabbage fields and responsibility of certain biotic factors for managing populations of this insect pest was the cornerstone of this investigation. Cabbage aphid, B. brassicae was found to be active on cabbage plantations and recorded in low numbers (99.71 individuals / 12.5 Cm 2 / leaf / infested plant) at the beginnings of the season (November) with gradual increase until harvesting. Three amongst the six evaluated cabbage cultivars and/or hybrids were appeared as susceptible (S) and harbored so high numbers of the pest. However, the remaining cultivars showed some sort of resistance to this insect pest. The local cultivar (Ganzory) harbored the least aphid numbers and appeared as moderately resistant (MR) cultivar. This finding could be attributed to the antixenosis and/or antibiosis phenomena presented by this local cultivar. Proteins and amino acid contents showed a highly significant positive correlation (r) with B. brassicae populations, however, chlorophyll showed highly significant negative (r). The obtained data reflect the role of the cabbage aphid parasitoid Diaeretiella rapae (McIntosh) to manage B. brassicae populations. Mummified aphids (parasitism rate) before harvesting were found to be equal 6.16 fold of that recorded before ripening stages. High percentages of D. rapae were succeeded to emerge from the mummified B. brassicae with diverse extrusion rates. Multiple increases were recorded on the percentages of infested plants when cabbage undergo toward ripening at the 9 th stage till harvesting. No or less existence of unmarketable plants (through the periods of the low infestation) before cup formation and/or plant ripening period was recorded. So, it can be concluded that cabbage cultivar, plant age, and stage in addition to plant metabolites combined with the naturally occurring biological control agent (Aphid parasitoid) can be affected and manage the population trend of cabbage aphid B. brassicae infesting cabbage in the field.
was higher on sandy soil (518 individuals / 120 leaves) than the clay soil (332 individual / 120 leaves), These results revealed significant positive effects of maximum and minimum temperature and DP on population density of P. operculella during the first season 2014 in clay soil and sand soil. The combined effect (E.V) of these ecological factors on P. operculella showed that these factors were responsible as a group for 84 %, 15% and 35 % effects on the population density of P. operculella throughout seasons (2014, 2015 and 2016) in clay and sandy soil , also, these factors were responsible as a group for 72 %, 64% and 26 % effects on the population density.
Faunistic composition and seasonal abundance of certain sap-sucking species inhabiting tomato and cucumber plantations were determined by using sweep net and direct count methods, during summer seasons of 2015 and 2016 in Assiut Governorate, Northern Upper Egypt. Twelve species belonging to 8 families and 3 orders in addition to the acarid mite were recorded. Heteropteran species were found to be constituted 69.24% of the gathered species. However, Homopteran species were found to be constituted 15.38%. Thysanoptera and Tetranichidae were presented by 7.69% for each. Concerning to the sampling method, 76.92% of the collected species were captured by the sweep net method, while 23.08% were gathered by the direct count method. The recovered species were classified as predominantly predaceous, predominantly phytophagous, predaceous in part and phytophagous in part species. Seasonal abundance of the recorded species was determined. The distinct predators, Coranus aegyptius (Fabricius, 1775) and Orius spp. showed relatively low abundance percentages. The predatory-phytophagous mirid species [Campylomma unicolor Poppius, 1914; Nesidiocoris tenuis (Reuter, 1895); Creontiades pallidus (Rambur, 1839). and Deraeocoris serenus (Douglas & Scott, 1868)], showed different abundance percentages. Amongst these taxa, N. tenuis revealed the highest abundance percentage on tomato plantations with an average of 63.00 and 75.00% during 2015 and 2016 seasons, respectively. The distinct phytophagous species, Thrips tabaci Lindeman, 1889; Bemisia tabaci (Gennadius, 1889) and Tetranychus urticae Koch, 1836 presented the greatest abundance percentages on cucumber when estimated by the direct count method. So, this work can be reflect the importance of sweep net as a suitable sampling method for determine the faunistic composition of the flight predatory insects inhabiting tomato and cucumber. However, direct count can be consider the most suitable method for determine the population trends of mobile or non-mobile arthropods inhabiting the same crops. Also, use of more than one sampling method could be successful to clarify the relation between useful and harmful arthropod species.
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