Effect of planting space and date on the population densities of certain insect pests infesting sweet pea plants ad Qalyoubia Governorate
2006
Emam, Azza K. | Hegab, Muhammad F. | Tanttawi, Maha A.
Four planting spaces of sweetpea seeds (10, 20, 30 and 40 cm) and four planting dates (Oct., 30th Nov., 15th Dec., 1st and Dec., 15th) were evaluated in 2001/2002 seasons to determine their effect on the population densities of certain sweetpea insect pests, i.e. thrips (Thrips tabaci Lind), aphids (mainly Aphis craccivora Koch, Acyrthosiphon pisum Harris and Myzus persicae Sulzer), leafminers (Liriomyza trifolii (Burg) and Chromatomyia horticola (Goureau) and whitefly (Bemisia tabaci Genn) infesting leaves or flowers. The largest planting space and earliest planting date harboured significantly the lowest seasonal mean numbers of all studied pests. The average numbers of the population densities of thrips, aphids, leafminers and eggs and nymphs of whitefly were 2.50, 1.05, 1.92, 4.05 and 4.26 individuals/leaflet/season and 1.24 and 0.82 individuals/flower/season for thrips and aphids infesting flowers, respectively for the largest distance ( 40 cm.). Meanwhile, the average numbers of the respective previous insects on the leaves were 5.84, 1.51, 1.29, 3.07 and 2.14 individuals/leaflet/season and 2.11 and 0.70 individuals/flower/season for thrips and aphids infecting flowers, respectively for the earliest planting date (Oct. 30th) in the first season (season 2001). On the contrary, the heaviest infestations were recorded on the sweetpea plants planted at closest planting space and latest planting date in the two tested season.
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