Effect of Horticultural Mineral Oil on Huanglongbing Transmission by Diaphorina citri Kuwayama (Hemiptera: Psyllidae) Population in a Commercial Citrus Orchard in Sarawak, Malaysia, Northern Borneo

Diaphorina citri Kuwayama transmits a destructive citrus disease caused by fastidious bacterium ‘Candidatus Liberibacter asiaticus’ (CLas) designated as Huanglongbing (HLB) which posed risk of detrimental threat to the Malaysian industry. All D. life stages show lumped habit on young flushes and its population fluctuations was closely related accessibility flushes. The study aimed investigate if appearance flush shoots influences ACP fluctuation horticultural mineral oil (HMO) could reduce spread HLB transmission in commercial healthy orchard. Field research carried out from 1 April 2011 December 2014 2-year-old ha farm that consisted 200 PCR-certified disease-free grafted non-bearing honey tangerine (Citrus reticulata L.) southwestern Sarawak, Malaysia. experiment had two treatments namely control (unsprayed) nC24 HMO with four replications arranged simple randomized block design. eggs, nymphs, adults per shoot assessed incidence monitored for visual inspection trees current existence usual signs characteristic symptoms such yellowing shoots, leaf mottling, corky or enlarged veins leaves. HLB-specific primer employed 16S rDNA polymerase chain reaction detect CLas gene diseased trees. Increase abundance is mainly affected flushing cycles their are completed these shoots. Relative degree aggregation index increased during periods cyclic production new flush. HMO-treated plots produced significantly lower percentage up 11.43% against 42.20% untreated plots. effective recommended be incorporated IPM program prevent infection HLB.