Control Of Asian Citrus Psyllid Research Articles

Comparison of insecticide sprays in alternate rows and in all rows on Asian citrus psyllid control and Huanglongbing progress in sweet orange orchards.

One strategy to reduce Huanglongbing (HLB) is controlling its insect vector, the Asian citrus psyllid (ACP) Diaphorina citri, by preventive insecticide sprays. The recommendation is to spray insecticide in all rows (conventional spray - CONV), but some growers empirically spray in alternate rows (ALT) to increase the spray frequency without increasing the operating cost. Therefore, this work compared the effect of ALT with CONV on the ACP population and HLB incidence. The spray deposition (amount of metallic copper per leaf area), coverage (percentage of water-sensitive paper area covered by spray), and efficacy (ACP mortality) of each treatment were also evaluated on both sides of the trees. Two field trials were performed: Trial #1 compared ALT every 7 days (ALT7) with CONV every 14 days (CONV14), and trial #2 compared different spray frequencies of ALT with CONV every 7 days (CONV7). In trial #1, no differences were observed in the ACP population or HLB progress between ALT7 and CONV14 after 5 years. In trial #2, ALT7 presented the highest percentage of ACP and cumulative HLB incidence than CONV7 and ALT every 3 to 4 days, after 2 years. Hence, when the frequency of ALT was half the frequency of CONV, similar results were observed. Spray deposition, coverage, and efficacy were similar between tree sides in CONV, but they were uneven in ALT, resulting in higher values on the tree side that directly received the spray. Insecticide spray should be performed with the frequency enough to keep new shoot protected during their growth.

HLB Progress and Yield Sustainability in Mature Sweet Orange Orchards Treated with Nutritional and Elicitor Products

Although the implementation of area-wide inoculum reduction and Asian citrus psyllid control are decisive in controlling Huanglongbing (HLB) epidemics, growers continue looking for enhanced nutritional and/or resistance inducer (ENRI) treatments to mitigate yield damage in HLB-affected trees. Therefore, an experiment was set up in an 8-year-old sweet orange orchard to evaluate the effects of the foliar application of nutrients, phosphite, and salicylate sprayed four to five times per year during flushing periods. The trial had eight treatments in four randomized blocks. HLB incidence and yield were assessed from December 2010 to January 2017. HLB-symptomatic trees with less than 5% HLB severity were selected from each plot in the first (Group 1), second (Group 2), and third years (Group 3) after the beginning of treatments to assess the frequency of trees with different HLB symptoms and micronutrient deficiencies, HLB severity, and fruit yield until January 2017. Twenty asymptomatic trees from each plot were also harvested for comparison each year. ENRI treatments did not reduce the progress of HLB incidence in the plots or the HLB severity progress or frequency of HLB symptoms in the selected trees. ENRI treatments did not improve the yield of symptomatic trees compared with asymptomatic trees. Hence, in a scenario without HLB-symptomatic tree removal in mature orchards, disease severity progress and yield reduction in HLB-affected trees remained regardless of ENRI treatment. [Formula: see text] Copyright © 2024 The Author(s). This is an open access article distributed under the CC BY-NC-ND 4.0 International license .

Isolation, fermentation, and formulation of entomopathogenic fungi virulent against adults of Diaphorina citri.

Mycopesticides are important for integrated management of the Asian citrus psyllid, Diaphorina citri. However, there are few reports on the fermentation and formulation for mycopesticides with high virulence against D. citri. From four different locations in South China, 12 fungal strains were isolated and classified into Beauveria bassiana (two isolates), Fusarium fujikuroi (five isolates), and Cordyceps javanica (five isolates) based on the phylogenetic analysis of ITS1-5.8S rDNA-ITS4 and morphology of colonies and conidia. Based on the highest initial virulence (86.52 ± 2.35%) and best growth characteristics, F-HY002-ACPHali was further optimized for biphasic fermentation (7.85 ± 2.62 × 109 g-1 dry substrate) with soybean meal + cottonseed flour (1:1) as the solid substrate and full light as the light/dark cycle. Furthermore, the oil-based conidial formulation was optimized with sesame oil as an effective carrier, which significantly enhanced conidial shelf life up to 16 weeks at 26 °C and 4°C, thermo-stress (50 °C) and UV-B stress resistance, and virulence against adults of D. citri with increased mortalities and decreased LT50 in comparison to that of unformulated conidia. Our results not only provide a valuable native strain with high virulence against adults of D. citri, but also imply the soybean meal + cottonseed flour as valuable solid substrate, full-light exposure as environmental stimuli for solid-state fermentation, and the sesame oil as an effective carrier for the formulation of the C. javanica. These findings will facilitate the development of a potential mycopesticide for the biological control of Asian citrus psyllid.

Comparison of Senstar to Commercially Available Insecticides for Control of Asian Citrus Psyllid on Orange, Summer 2020

Comparison of Senstar to Commercially Available Insecticides for Control of Asian Citrus Psyllid on Orange, Summer 2020

RNA interference-mediated control of Asian citrus psyllid, the vector of the huanglongbing bacterial pathogen

Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Liviidae), is the natural vector of the Huanglongbing (HLB) pathogen that presents an unparalleled challenge to citrus production. RNA interference (RNAi) has already shown great potential for insect pest management owing to its high specificity. RNAi technique relies on the delivery of exogenous double-stranded RNAs (dsRNAs) that target essential genes in insects. The D. citri genome possesses three dsRNase homologs and all core RNAi machinery genes, aside from the R2D2 that functions as a cofactor of Dicer-2 in the siRNA pathway. Nevertheless, ever-increasing research on the application of RNAi to suppress D. citri population has promulgated outstanding progress. Here, we provide a comprehensive review of the recent literature, and summarize the current understanding of RNAi mechanisms and advances in the applications of RNAi in D. citri. The major challenges including the potential of dsRNA degradation, target gene selection, and dsRNA delivery methods, as well as the implications of using RNAi for D. citri control are reviewed.

Single and Multiple Modes of Action Insecticides for Control of Asian Citrus Psyllid and Citrus Leafminer

Control of Asian citrus psyllid Diaphorina citri Kuwayama and citrus leafminer Phyllocnistis citrella Stainton is important to reduce the spread and severity of huanglongbing (HLB) (citrus greening) and citrus canker diseases, respectively. Insecticides are critical for the management of these pests. We therefore conducted two replicated experiments using spray treatments containing single or multiple modes of action (MoA) insecticides to reduce the incidence of these two pests in bearing citrus. Tank mixing in 47 L·ha−1 (5 gal/acre) of water with synthetic plant terpenes (Requiem 25 EC, Unknown MoA) or adjuvant petroleum oil (PureSpray Green, Unknown MoA) did not improve the effectiveness of the pyrethroid zeta-cypermethrin (Mustang Max 0.15 EC, MoA 3A) against D. citri. Its control with flupyradifurone (Sivanto 200 SL MoA 4D) and PureSpray Green in 935 L·ha−1 (100 gal/acre) water was similar to Mustang Max 0.15 EC and Requiem 25 EC, but mixtures did not provide better control than Mustang Max 0.15 EC alone. Phyllocnistis citrella was controlled only with Sivanto 200 SL and PureSpray Green and Requiem 25 EC alone. The addition of cyantraniliprole (group 28 MoA in A16971 premixed with thiamethoxam MoA 4A), pymetrozine (Fulfill 50 WDG, MoA 9B), or abamectin (Agri-Mek SC, MoA 6) did not improve and in many cases reduced the performance of thiamethoxam (Actara 25 WG, MoA 4A) against D. citri and P. citrella. These results demonstrated no advantage to single applications of multiple MoAs over the most effective active ingredients when applied alone for control of D. citri or P. citrella. Therefore, rotations of these active ingredients would be preferable to mixtures to avoid selection for resistance against multiple MoAs by any one application.

Control of Asian Citrus Psyllid and Citrus Leafminer with Cyantraniliprole, Cyclaniliprole and Flonicamid: Summer, 2015

Asian citrus psyllid (ACP) is the key pest of citrus in Florida, responsible for the spread of huanglongbing or citrus greening disease. Feeding damage from CLM larvae facilitates the spread of citrus canker. Insecticides are critical for suppression of these two pests. The experimental block at the Southwest Florida Research and Education Center consisted of 5-yr-old sweet orange “Hamlin” trees bud grafted to “US-802” (Citrus grandis × Poncirus trifoliata) planted at a density of 308 trees/acre. Trees were irrigated with microsprinklers and subjected to conventional cultural practices. Eight treatments and an untreated check, seven trees per plot, were randomly distributed …

Beleaf and Other Insecticides for Control of Asian Citrus Psyllid During Bloom: Spring, 2015

Asian citrus psyllid (ACP) is the vector responsible for the spread of “Huanglongbing” or citrus greening disease in Florida and therefore is the key pest of citrus. Control is critical throughout the year, including spring, when trees produce new growth required by ACP to develop and reproduce but when presence of bloom limits insecticide choice. The experimental block at the Southwest Florida Research and Education Center consisted of 5-yr-old sweet orange “Hamlin” trees bud grafted to “US-802” ( Citrus grandis × Poncirus trifoliata ) planted at a density of 308 trees/acre. Trees were irrigated with microsprinklers …

Organic Insecticides for Control of Asian Citrus Psyllid and Citrus Leafminer on Oranges, Fall 2014

ACP is the key pest of Florida citrus due to its role as vector of greening disease or “huanglongbing.” Feeding damage from CLM larvae facilitates spread of citrus canker caused by Xanthomonas axonopodis pv. citri . The present trial is a result of our recent effort to evaluate options for controlling these pests with organically approved insecticides. The experimental block located at a commercial grove near Labelle, FL, consisted of 12-yr-old “Hamlin” sweet orange planted at a density of 132 trees per acre. Eight treatments and an untreated check were randomly distributed in an RCBD with four replicates in five-tree plots over nine rows with one untreated buffer row between treated rows and one untreated buffer …

Evaluation of Organophosphate and Pyrethroid Insecticides for Control of Asian Citrus Psyllid and Citrus Leafminer on Oranges, Summer, 2014: Table 1

ACP is the key pest of Florida citrus due to its role as vector of greening disease or “huanglongbing.” Feeding damage from CLM larvae facilitates spread of citrus canker caused by Xanthomonas axonopodis pv. citri . Both pests feed on young flush and are also damaging in their own right. Therefore, effective insecticides are needed. The experimental block at a commercial grove near Labelle, FL, consisted of 12-yr-old sweet orange “Hamlin” orange trees planted at a density of 132 trees/acre. Seven treatments and an untreated check were randomly distributed …

Tank Mixes and Premixes of Experimental and Labeled Insecticides for Control of Asian Citrus Psyllid and Citrus Leafminer on Oranges, Summer, 2014: Table 1

ACP vectors the bacterium Candidatus Liberibacter asiaticus, causal organism of citrus greening disease or “Huanglongbing.” Feeding damage from CLM larvae facilitates the spread of citrus canker caused by Xanthomonas axonopodis pv. citri . Effective control measures are needed upon which to develop integrated management strategies against these pests and the associated diseases in Florida citrus. The experimental block in a commercial grove near LaBelle, Florida consisted of 7-yr-old sweet orange “Hamlin” trees planted at a density of 132 trees/acre. …

Comparison of Organic to Some Conventional Insecticides for Control of Asian Citrus Psyllid and Citrus Leafminer on Oranges, Spring 2014

ACP is the key pest of Florida citrus due to its role as vector of greening disease or “huanglongbing.” Feeding damage from CLM larvae facilitates spread of citrus canker caused by Xanthomonas axonopodis pv. citri . Organic citrus growers have few proven alternatives for controlling these pests, providing the motive for this trial. The experimental block located at a commercial grove near Labelle, FL, consisted of 12-yr-old “Hamlin” sweet orange planted at a density of 132 trees per acre. Ten treatments and an untreated check were randomly distributed in an RCBD with four replicates in five-tree plots over four rows with one untreated buffer row between treated rows and one untreated buffer tree between plots …

Bionomics of Asian Citrus Psyllid (Hemiptera: Liviidae) Associated with Orange Jasmine Hedges in Southeast Central Florida, with Special Reference to Biological Control by Tamarixia radiata.

The Asian citrus psyllid, Diaphorina citri Kuwayama, is an important pest in Florida because it transmits bacteria responsible for citrus huanglongbing disease. In addition to infesting citrus, orange jasmine (Murraya exotica L.) is one of Asian citrus psyllid's preferred host plants and is widely grown as an ornamental hedge. We report on Asian citrus psyllid bionomics over three years at five urban plantings of orange jasmine and on biological control of Asian citrus psyllid by a parasitoid Tamarixia radiata (Waterston). T. radiata had been released in Florida shortly after Asian citrus psyllid was first found, and the parasitoid was known to be established at each planting. Additionally, three new T. radiata haplotypes were released every 3 wk at three plantings during the first study year (one haplotype per planting, over all releases an average of 17 parasitoids per linear meter of hedge); all three haplotypes were released at a fourth planting beginning midway through the study (over all releases, an average combined total of 202 parasitoids per linear meter of hedge). Asian citrus psyllid populations were present year-round at each planting, often at large levels. Such plantings may pose risk to commercial citrus as Asian citrus psyllid reservoirs. Releases of the new haplotypes did not cause any measurable reduction in Asian citrus psyllid population levels during the study, and ironically percentage parasitism was generally highest at a planting where no releases were made. Higher release rates might have been more effective. The probability is discussed that repetitive pruning of orange jasmine reduced the full potential of T. radiata against Asian citrus psyllid in this study.

Soil Applied Systemic Insecticides for Control of Asian citrus psyllid in Newly Planted Citrus Trees

Orchard renewal is a special challenge where HLB is endemic.  Young trees are especially susceptible to the disease and continuously attractive to the psyllid vector due to frequent flushing.  Heavy reliance is placed on systemic insecticides to protect young trees.  However, all presently labeled for citrus are neonicotinoids (IRAC Group 4a) making resistance likely and the long term viability of this strategy questionable.  Rotation partners are needed to forestall selection for resistance. Therefore, we conducted a multiyear study to evaluate rotations of neonicotinoid insecticides rotated with cyantraniliprole a Group 28 insecticide in a block of ‘Hamlin’ orange on ‘US802’ rootstock planted in May 2010. Four treatment programs using two rates of Verimark 20 SC, rotated with Platinum 75 and Admire Pro in two different sequences were compared to an untreated check in an RCBD with 4 replicates.  Adult psyllid populations were monitored monthly and immatures counted when natural flush was present.  Incidence of HLB was assessed by PCR in Aug 2011, and Jan, May and Aug 2012. Psyllid populations on treated trees averaged 1.43 per tap compared to a range of 0 to 0.8 on treated trees.  Incidence of HLB reached 29% in Aug 2011 on untreated trees compared to 0-8.3% on treated trees.  In May 2012 these numbers had increased to 67 % and 11-26% respectively.  Diameter of scions was 33% larger on treated trees in Sep 2012.  Although effective, the 90 day treatment regimen was not enough to protect trees from HLB and additional strategies are necessary.

Efficacy and Uptake of Soil-Applied Imidacloprid in the Control of Asian Citrus Psyllid and a Citrus Leafminer, Two Foliar-Feeding Citrus Pests

The systemic neonicotinoid insecticide imidacloprid, Admire Pro, was applied to 3- and 4-yr-old nonbearing 'Rio Red' grapefruit, Citrus x paradisi Macfad., trees in 2006 and 2007, respectively, to determine its effects in the control of two major citrus pests, the Asian citrus psyllid, Diaphorina citri Kuwayama (Hemiptera: Psyllidae), and a citrus leafminer Phyllocnistis citrella Stainton (Lepidoptera: Gracillariidae). Young flush shoots were randomly collected weekly for 13 and 11 wk in 2006 and 2007, respectively, to determine the infestation levels and densities of immature stages of both Asian citrus psyllid and P. citrella. Additional flush shoot samples were collected in 2007 and titers of imidacloprid in leaf tissue were determined using an enzyme-linked immunosorbent assay. Soil application of imidacloprid significantly reduced the infestation levels and densities of both pests on flush shoots, starting from the second week post application. The effects of the neonicotinoid insecticide were similar in both years. Analysis of imidacloprid concentration in leaf tissue showed a gradual increase during the first 3 wk, and titers remained well above 200 ppb for 11 wk postapplication. Significant positive correlations were obtained between imidacloprid titers in leaf tissue and the percentage of control levels achieved for both pests. A high level of suppression of both P. citrella and Asian citrus psyllid populations on citrus trees was associated with imidacloprid titer in leaf tissue >200 ppb, which was reached 2 wk after soil treatment. Although soil application of imidacloprid did not provide rapid knockdown of Asian citrus psyllid and P. citrella populations, it resulted in chronic residues in leaf tissue and long-term suppression of both pests.