1a. Objectives (from AD-416)
1. To screen citrus species and related species in the USA and China for resistance to the Asian citrus psyllid. 2. To identify plant traits which impart resistance to the psyllid, traits that could be used to develop commercial citrus varieties with psyllid resistance for the purpose of reducing incidence of huanglongbing disease.
1b. Approach (from AD-416)
Subject candidate citrus species and related species in free-choice infestation studies and determine species that are avoided by the psyllid for food and reproduction. Evaluate these apparently resistant plant species in no-choice studies to confirm they are avoided by the psyllid. Plant resistant species in the field and monitor them over time to determine if they develop huanglongbing.
3. Progress Report
This project is related to Objective 3c: Investigate basic biology and ecology of the Asian citrus psyllid and its natural enemies in Florida citrus. Citrus germplasm (87 genotypes including citrus relatives) was assessed in a field study for resistance to natural South Florida populations of the psyllid. The majority of genotypes surveyed hosted all three life stages of the psyllid; however, there were significant differences among genotypes in infestation levels of eggs, nymphs and adults. Although not completely avoided, very low levels of the psyllid were found on two surveyed genotypes of Poncirus trifoliata, Simmon’s trifoliate and Little-Leaf. Poncirus trifoliata readily forms hybrids with other citrus germplasm, is commonly incorporated into rootstock varieties, and has been used in breeding advance scion material. The identification of partial resistance in P. trifoliata to the psyllid may prove useful in future citrus breeding efforts aimed at reducing the incidence and spread of huanglongbing.