Manipulating Orchard Ground Cover to Reduce Invasion by Leafhopper Vectors of Peach X-Disease1

Abstract

Adults of six leafhopper vectors of X-disease. Colladonus clitellarius (Say). Fieberiella florii (Stal). Gyponana lamina DeLong. Norvellina seminuda (Say). Paraphlepsius irroratus (Say), and Scaphytopius acutus (Say) invaded an experimental peach block in Hamden, Conn. The number and species of leafhoppers captured on clear sticky traps hung in peach trees 6 m apart varied depending upon which of four different ground cover types was beneath. The greatest number of adult leafhoppers trapped between 10 June and 28 October 1980 were from plots where ground cover was pure red clover, Trifolium pratense L. ( n = 1,115). Significantly fewer adults were trapped on peach trees with mixed weeds, mainly rosaceous species ( n = 575). pure orchard grass, Dactylis glomerata L. ( n = 364). or bare ground ( n = 211) beneath. Most S. acutus ( n = 878) occurred on trees with red clover beneath. whereas relatively few occurred on trees with either orchard grass or bare ground beneath. The most abundant leafhopper vector. P. irroratus . ( n = 1,289) did not discriminate among ground cover types; a substantial portion of the population was captured on trees in all but the plots with bare ground. Managing the orchard floor free of host plants to discourage invasion by leafhopper vectors may reduce the spread of peach X-disease.