Asian citrus psyllid

Asian citrus psyllid (ACP), Diaphorina citri Kuwayama (Hemiptera: Liviidae), is a severely devastating pest of Rutaceae plants, mainly citrus, across the globe, and causal agent of Huanglongbing (HLB) disease. To find out the genetic relationship and diversity among the populations of ACP and associated Candidatus Liberibacter asiaticus (CLas) from two countries (China and Pakistan), sequence data of three different genes, cytochrome oxidase subunit I (COI), Cu-transporting protein (ATOX1) and 16S rRNA, were used to characterize all populations. In the present study, MEGA-7 and statistical parsimony software (TCS-1.2) were used to depict the phylogenetic relationship among all populations under both genes, whereas diversity was calculated by DnaSP v5. All analyses were done for country wise and overall relationship among all populations. For ACP populations, both genes presented a significant strong intermingled relationship among all populations and put all population into a single haplotype (Dcit-2), which proved similarity between Chinese and Pakistani populations. Moreover, for CLas strains, 16S gene also presented strong relationship for all sampled populations. All three genes of ACP and CLas populations elucidated more than 95% resemblance to each other. On the other hand, a significant genetic variation was observed by three genes for overall populations, although, country wise variation was non-significant between all collected populations. ATOX1 gene presented higher diversity through Fu's Fs test (π = 0.01081, p < 0.003) whereas COI gene gave less diversity under Fu's Fs and Tajima's D test (π = 0.00512, p < 0.000 and 0.05, respectively). Similarly, nucleotide mismatch distribution also had shown enough genetic variation among all ACP populations, under both genes. Our sequence data for both genes proved the invasion of the Chinese ACP population (Dcit-2) into Pakistan, through all phylogenetic relationship, which proved a similar genetic makeup among all ACP populations from both countries. Therefore, these results can be helpful to utilize any novel designed control measure equally for both countries.

The experiments were conducted in a citrus orchard to check the efficacy of insecticides against citrus psylla, and mortality was observed after three days, seven days and then after one month. Four insecticides, Polytrin-C, Talstar, Bifenthrin and Imidacloprid applied, had an almost equal effect on the population reduction of citrus psylla on all citrus plants. The trial was laid out in randomized complete block design (RCBD) having five treatments with three replications in a citrus orchard, after three days of spray showed percentage control as 96.91%, 94.33%, 93.83% and 93.06% of following insecticides Polytrin-C, Imidacloprid, Bifenthrin and Actara, respectively, calculated by Minitab 15. Psylla adults were exposed to different concentrations (500, 400, 300, 200 and 100 ppm) of Imidacloprid and Bifenthrin, and two controlled conditions (with leaves and without leaves). Both Imidacloprid and Bifenthrin insecticides proved to be the most effective against D. citri with lethal times (LT50s) of 4 and 5 hours, respectively, at a concentration of 500 ppm, calculated from probability test with Minitab-15.

The second largest fruit crop of the world, citrus is a high prospect sector in Nepalese hills. Citrus greening (Huanglongbing) is the most complex, challenging, incalcitrant and devastating disease that has threatened the citrus industry worldwide. Citrus Decline in Nepal is claimed to be because of HLB coupled with other diseases and grove management practices. This disease is spread by a sucking insect, the Asian Citrus Psyllid (ACP); by controlling its population the spread of HLB to new groves could be prevented. This review article comprises the best method for rapid detection of HLB and chemical, biological and cultural management practices for controlling ACP to prevent the spread of HLB in Nepal. Iodine based test can be used to screen the samples infested with HLB which could be confirmed after molecular HLB testing i.e. PCR. Chemically, ACP could be best managed by intensive chemical spray during the critical flushing periods and winter. Biologically, ACP could be best managed by the use of parasitoids, predators and pathogen that consumes and destroy ACP nymphs/or adults. Culturally, the spread of ACP could be best managed by protective cultivation, reflective mulch and growing nurseries to produce saplings at high altitudes in Nepal for preventingthe spread of HLBin new groves.

This paper summarizes Australia&#39;s contingency planning in the event of incursions of huanglongbing and its known vectors, the Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Sternorrhyncha: Psylloidea: Psyllidae) and the African citrus psyllid Trioza erytreae del Guercio (Hemiptera: Sternorrhyncha: Psylloidea: Triozidae). The plan aims to provide information relevant to the implementation of PLANTPLAN: Australian Emergency Plant Pest Response, (Plant Health

The entmopathogenic fungus Lecaniicillium lecanii is a naturally available biological control and it is considered to be one of the best mycoinsecticide agents against the destructive insect pest Diaphorina citri Kuwayama. The present study aimed to extract and characterize the toxic insecticidal protein from L. lecanii and to assess the toxicity level against the Asian citrus psyllid the vector of Huanglongbing disease (HLB), also called citrus greening. Extracts of a toxic substance from submerged batch culture examined by sodium dodecyl sulfate-poly-acrylamide (SDS-PAGE), had a molecular weight of 45 kDa. The most abundant toxic metabolite was subjected to HPLC to purify and identified it by mass spectrometry. Subsequently, metabolite toxicity was tested against D. citri at three different concentrations (1%, 2%, and 3%). The results showed that the highest concentration had a significant maximum mortality at 120 h post application. Furthermore, we investigated the expression of the GAS1 gene which was previously identified to have a role in pathogenicity in in vivo studies in adult insect psyllids. Results of this study indicated that expression of the virulence factor gene was present at three concentrations of the fungal suspension post inoculation. This is the first study to provide this novel approach for the characterization of fungal mediated synthesis of a cuticle degrading soluble protein against the insect D. citri. The present results provide strong information on the in vivo expression of the GAS1 gene involved in fungal virulence pertaining to penetration of the insect cuticle, but not to inhibiting the growth of the host.