PERFORMANCE EVALUATION OF MYZUS PERSICAE ( SULZER ) ( HEMIPTERA: APHIDIDAE ) ON S. BERTHAULTH ( HAWKS ) XS. TUBEROSUM (L.) THROUGH TWO METHODOLOGIES

Abstract

A research was carried out with the purpose of studying the behaviour of the green peach aphid, Myzus persicae (Sulzer), on the foliage of l0 genotypes of hybrid potatoes obtained of crossing between Solanum berthaultii x Solanum tuberosum. They are characterized for the presence of glan-dular trichomes A and B in their foliage. The study included also a control that corresponded to S. tuberosum cv. Atica.
In this research two methodologies to measure plant resistance were used, the first with intact plants and the second with excised leaf plants. Both methods were carried out under controlled temperature (20-25 ºC) and photoperiod (16:8) with the objective of determining the way in which the hybrid affected M. persicae.
In order lo determine the aphid behaviour on the foliage and detached leaves, measurements were made on developmental time, survival, adult weight and aphid fecundity. Relationship between the characteristic of the plant (densities of trichomes type A and B, and concentration of enzyme polyphenol oxidase) and aphid behaviour were evaluated.
The aphid performance was in general, affected by the hybrids in comparison to the control. This was notorious mainly in the genotypes Q132-1, Q 132-16. Q132-22, P161-3 and P161-8.
The methodology of excised leaf, can be used to evaluate resistance against aphids being particularly, easy manipulate aphids with this techniques. This methodology could be suitable when a large quantity of material need to be tested. However (he use of removed leaves diminished the expression of resistance of the plant, due to the physiological changes that it suffers, what ends up reducing the detrimental effect of plants on aphids.