ECOLOGICAL STUDIES ON SOME HOMOPTEROUS INSECTS INFESTING CERTAIN CITRUS AND GUAVA TREES

Abo-Alnor, Fatma A.I.; Hegab, Ola I.M.; Hegab, A. M.; Abd-Elsamad, A. A.

doi:10.21608/zjar.2016.99783

ECOLOGICAL STUDIES ON SOME HOMOPTEROUS INSECTS INFESTING CERTAIN CITRUS AND GUAVA TREES

Document Type : Original Article

Authors

¹ Plant Prot. Res. Inst., Agric. Res. Cent., Dokki, Giza, Egypt.

² Plant Prot. Dept., Fac. Agric., Zagazic Univ., Egypt

10.21608/zjar.2016.99783

Abstract

The present work was conducted during the two successive seasons of 2012/ 2013 and 2013/2014 in order to survey and study the population density of aphids, leafhoppers and whitefly insects infesting navel orange (Citrus sinensis), mandarin (Citrus reticulate) and guava (Psidium guava) trees in Diarb-Nigm District, Sharkia Governorate, Egypt. Aphidspecieswere Aphis citricolla (Goot) and Aphis gossypii (Glover). Leafhopper insect species included Empoasca decipiens (Paoli), Empoasca decedens (Paoli), Cicadulina chinai (Ghauri) and Planthoppers were Sogatella vibix (Haupt) and S. furcifera (Horv), while whitefly species was Bemesia tabaci (Genn.). The aforementioned insects were collected by three different sampling techniques from navel orange, mandarin and guava trees i.e., plant sample, sweeping net and yellow sticky board trap. The obtained results showed that the plant sample proved to be the best method to collect both aphid and whitefly insects of the present work, while sweeping net proved to be the best technique to collect the leafhopper and planthopper insects. The seasonal abundance of A. citricolla on navel and mandarin trees showed one peak of population density, which occurred at the 4^th week of March, for the two investigating seasons. While, A. gossypii on navel orange and mandarin trees showed three peaks of population density. The first one occurred at the 4^th week of November. The second peak was recorded at the 4^th week of March for both seasons. The third peak was recorded at the 4^th week of June (2012/ 2013) and the 2^nd week of July (2013/2014) on navel orange trees but on mandarin trees, it was at the 2^nd week of June in both seasons. While, on guava trees two peaks of population density were recorded at the 4^th week of August and the 4^th week of June in both seasons. Whitefly B. tabaci showed three peaks on citrus trees which were at the 4^th week of November, the 2^nd week of April and August in both seasons, respectively, but on guava trees they were at the 4^th week of October and April in both seasons, the third peaks were at the 2^nd week of February (2012/2013) and the 2^nd week of January (2013/2014). Three peaks, the first two peaks for E. decipiens and E. decedens on citrus trees were occurred at the 4^th week of October and the 2^nd week of June during the two seasons and the third peak was at the 2^nd week of July for E. decipiens in both seasons and for E. decedens at the 4^th week of June and the 2^nd week of July, but on guava trees were at the 4^th week of October and April in the two seasons, respectively. C. chinai, S. vibix and S. furcifera had two peaks occurred at the 4^th week of October and the 2^nd week of September for the two seasons on citrus trees and the third peak of C. chinai was on navel orange trees at the 2^nd week of June and the 4^th week of May at the two seasons, but on mandarin trees was at the 4^thweek of June. The third peak of S. vibix on navel orange trees and S. furcifera, was at the 2^nd week of May while it was at the 2^nd week of May on the season of (2013/2014), but the third peak of S. vibix was on mandarin trees at the 4^th week of March, and the 2^nd week of April and for S. furcifera the third peak was at the 4^th week of March in both seasons, respectively.

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