Population dynamics and control of the citrus rust mite, Phyllocoptruta olievora (Ashmead)‎ infesting orange trees in Egypt

الملخص EN

The population dynamics of the citrus rust mite are affected by many factors.

The population fluctuation and control of the citrus rust mite Phyllocoptruta olievora by using different pesticides were investigated on Valencia orange trees in Wadi El-Natroun, Bohaira, Egypt during two seasons of 2015 and 2016.

In the first season of 2015, the first appearance of the mite individuals on orange trees (summer crop) started, noticed and recorded in April, 11th and these individuals were vanished on October, 28th.

The mite was found to have three peaks of activity; the 1st peak appeared in the second week of May.

The 2nd peak was noticed by the end of June and the 3rd peak is shown in the 2nd week of September.

During the season of 2016, the beginning of the presence of the mite individuals on the leaves was recorded on April, 30th.

The end of the presence of the mite individuals was also observed on September, 27th .

Also, it was noticed that the mite was found to have three activity peaks during the season of 2016 in the same experimental area.

The 1st higher peak was shown in mid-June, the 2nd peak was seen in the first week of July, while the 3rd peak occurred during the last week of August.

During these peaks periods of 2105 and 2016, the temperatures were appropriate for the mite activity and they were of 30° C range or more (30-34.5).

Eight pesticides (hexythiazox, fenpyroximate, chlorfenapyr, abamectin, spirodiclofen, spirotetramat, petroleum oil and sulfur) were selected to control P.

olievora.

The calculation of the reduction percentage of 3 inspections after the 1st, 2nd and 3rd spray showed that abamectin was the most effective compound during both seasons of 2015 and 2016 giving percentage reduction means of the mite individuals of 90.0, 90.4 and 90.3% (2015) and 92.9, 95.2 and 96.3% as compared with the other tested compounds during 2106.

Meanwhile, both sulfur and petroleum oil were the least effective evaluated pesticides, nevertheless, the general mean of mite individuals reduction (GRM) they caused was not less than 66.0 or 73.0% during the two seasons of study (2015 and 2016).