دراسات على حشرة الحمضيات الموالح الرخوة Coccus pseudomagnoliarum (Kuwana)‎ على الحمضيات الموالح في الساحل السوري و تقويم كفاءة المفترسات المصاحبة لها

الملخص EN

The citrus soft scale (Citricola scale), Coccus pseudomagnoliarum, (Kuwana) (Homoptera: Coccidae) is an important pest on citrus trees along the Syrian coast.

This study was carried out at the Agricultural Research Center in Lattakia (Ciano) during the period 2008-2010.

Samples were collected from three citrus cultivars (Satsuma, Clementin and Washington Navel).

Three trees and five shoots from each tree were randomly selected from each cultivar.

The shoots were collected from the four directions in addition to one from the middle.

Samples were transferred to the laboratory for inspection.

Fifty leaves from each cultivar were inspected.

Results obtained showed high density of the pest stages, in May and first half of June, 2008.

Two species of predators (Chilocorus bipustulatus, Serangium parcesetosum Sicard) were recorded associated with the pest stages on the citrus trees.

Comparative efficacy assessment of the two predator species was carried out in cages.

The experiment included three treatments.

In the first and second treatments, each predator species was released at the rate of 3 predators/seedling.

The releases were made three times, once every 10 days.

The third treatment was the control.

Citrus leaves and shoots were tested monthly.

Average nymphs density of the pest was 6.1±0.8, 3.1±0.3 and 8.0±0.7 nymphs/5 cm2 of leaf surface, before the release of the predators in the three treatments, respectively.

Nymphs population density was reduced significantly in the predator treatments, reaching 1.7±0.8 nymphs/5cm2 leaf surface, 4 weeks after the release and to 0.98±0.2 nymphs/5cm2 10 weeks after the release of S.

parcesetosum.

Changes in the nymphs density were not significant following the use of another predator.