Two pear accessions evaluated for susceptibility to pear psyllaCacopsylla bidens(Šulc) in Israel

Abstract

The resistance mechanism in both accessions appears to be antibiosis affecting nymph survival. These resistant accessions may be used as rootstock or as a source of resistant genes in breeding programmes.

Grafting on resistant interstocks reduces scion susceptibility to pear psylla, Cacopsylla bidens

“…To determine whether resistance to psylla could be transferred by grafting, in 2005 Spadona shoots were grafted on 13‐year‐old trees of the resistant accessions ‘760’ and ‘701’ (two trees each). These trees were originally grafted on P. betulifolia rootstock, in the Israeli pear collection orchard at Newe Ya'ar, and found to have 10 and five times lower natural pear psylla infestation, each, compared with Spadona grafted on P. betulifolia rootstock. Planting distance was 4 m between trees and 4.5 m between rows.…”

“…There was barely any psylla damage to the fruit in the experimental orchards even though they did not receive any pesticide treatment. As all other pear orchards at the station were severely infected by psylla, one possible explanation for the very low number of psylla in our experimental plot could be production of volatiles by the resistant trees which either killed or repelled the psylla . Although specific volatiles were not identified here, it is worthwhile to note that the involvement of such in female attraction was previously shown for the pear psylla C. bidens .…”

“…Based on field, semi‐field, and laboratory tests, we found that accession ‘760’ 760‐261 was ten times more resistant than ‘Spadona Estiva’ ( Pyrus communis L.) (Spadona), the common commercial pear cultivar in Israel, while ‘701’ was five times more resistant. The resistance mechanism in both accessions appears to be antibiosis affecting nymph survival . As ‘760’ and ‘701’ were found to be unsuitable for commercial use because of low fruit quality (small, tasteless fruits with a high amount of stone cells), the first alternative considered was to use them as rootstocks.…”

“…In a previous study, we found that two accessions from the Israeli local live collection at Newe Ya'ar Research Center, ‘760’ and ‘701’, are resistant to the pear psylla C. bidens . Both of the accessions are apparently of Pyrus communis L. origin.…”

Genetic mapping of Cacopsylla pyri resistance in an interspecific pear (Pyrus spp.) population

“…The most damaging psylla species identified are Cacopsylla pyri (Linnaeus), endemic to Europe, Cacopsylla pyricola (F rster) to Europe and North America, and Cacopsylla bidens (Ŝulc) to Europe and the Middle East (Shaltiel-Harpaz et al 2014). The pear psylla life cycle begins with the eggs, laid singly or in clusters on the host plant, which hatch into nymphs that go through five instars (Atger and Bigre 1982) (Fig.…”