INTEGRATED CONTROL OF RED SPIDER MITE TETRANYCHUS URTICAlKOCH ON STRAWBERRY PLANTS

Abstract

The present work aimed to study the population dynamics of both phytophagous and predatory mites associated with two strawberry cultivars (Sweet -Charlie and Comarosa), study the host plant resistance (chemical and physical factors) and effect of fertilization on mite infestation. Also, the efficiency of different control methods ( chemical and biological) for controlling these phytophagous mite. The obtained results revealed that:

1- The rate of infestation was higher in Comarosa than on Sweet-Charlie cultivar, population density was so higher at Giza followed by Ismailia and Qalubia. The peak of population in all localities was occurred during February and March. Three predatory mites were recorded, Amblyseius swirskii (Athias-Henriot), Amblyseius zaheri (Yousif & El-Brolosy) and Amblyseius barkeri (Huges) at Ismailia, Qalubia and Giza, respectively. The predatory insect (Oruis sp.) was recorded at February, reaching its peak during March. The population of T urticae stages had a positive correlation with air temperature, while it had negative correlation with relative humidity.

2- Sweet- Charlie cultivar was higher than Camarosa in total phenols and amino acids, while the opposite was recorded for total sugars. Trichomes of Sweet-Charlie are longer and have more sharply and pointed end. Population density of Sweet-Charlie trichomes was higher than those of Camarosa. Fertilization with CaSo4 or K2S04 reduced and laten infestation by spider mites to the first half of March, annd increased total phenols and amino acids in both cultivars compared with control.

3- Evaluation the efficiency of Vertemic, Plant-Guard, Micronised sulfure and Sumite during two seasons was studied. Vertemic revealed that it was the compound which had good reduction percentages in all mite stages, while Sumite and Plant-Guard were the

lowest efficiency compounds. Micronised sulfur was moderate efficiency compound. The higher reduction percentages of Vertemic was occurred on immatures, followed by adults, while eggs had the lowest reduction percentages duringtwo seasons.

4- The exotic predatory mites Amblyseius californicus (McGregor) and Phytoseiulus persimilis (Athias-Henriot) gave excellent biological control, while the indigenous species Euseius scuta/is (EI-Badry) and A. barkeri (Huges), gave medorate control.

5- The Vertemic was the best treatment in increasing of strawberry yield by the exotic predatory mite Acalifornicus and Pipersimtlis, while indigenous predators gave moderate increasing in yield. The other pesticides and both fertilization treatments gave lowest percentage of increasing in strawberry yield.