Seasonal Abundance of Brevipalpus phoenicis (Acari: Tenuipalpidae) and Its Predators and Their Effects on Gerbera jamesonii Morphology

Abstract

The objective of this research was to study the abundance and prevalence of Brevipalpus phoenicis and its predators on Gerbera jamesonii Bolus and its relation with different weather variables during a one-year study 2015 at Ismailia Governorate, Egypt. The abundance of B. phoenicis life stages was monitored monthly. The effects of mite's infestation on G. jamesonii morphology represented in leaf, flower, bud and flower deformity numbers during spring was considered, in addition to the photosynthetic pigments. Our results revealed great variations in mite population throughout the year. The highest density of B. phoenicis adults, eggs, larvae, nymphs were recorded in January (50.25±6.08), May (71.85±8.57), January (31.40±4.71), July (74.43±8.73), respectively while the minimum density were recorded in October (4.10±0.83), September (10.30±2.09), August (1.95±0.46) and (16.10±2.50), respectively. Three predacious mites: Amblyseius cucumeris, Hemicheyletia wellsina, Tydeus sp. and one predacious insect Scolothrips longicornis were recorded. Negative correlations was recorded between B. phoenicis eggs or larvae with S. longicornis (-0.122,-0.168), respectively. Significant negative correlations were observed between different B. phoenicis life stages, Tydeus sp. and S. longicornis with temperature and relative humidity. There were significant negative or positive correlations between life stages of B. phoenicis and the morphological characteristics of the plant. Highly significant negative correlation was recorded between mite infestation and photosynthetic pigments. In conclusion, G. jamesonii is recorded as a new host for B. phoenicis with a marked deformation in the plant morphology. In addition environmental factors had a great effect on its abundance.