Insecticidal Suppression of Asian Citrus Psyllid Diaphorina citri (Hemiptera: Liviidae) Vector of Huanglongbing Pathogens

Abstract

Diaphorina citri vectors pathogens that cause ‘huanglongbing’ or citrus greening disease which poses a serious threat to citrus production worldwide. Vector suppression is critical to reduce disease spread. Efficacy is a main concern when choosing an insecticide. Insecticidal treatments of 49 products or 44 active ingredients (a.i) labeled or experimental were field tested between 2005–2013 as foliar sprays (250 treatments, 39 a.i) or soil applications (47 treatments, 9 a.i) to control D. citri in citrus. A combined effect of nymphal and adult suppression in response to sprays of 23 insecticides representing 9 modes of action (MoA) groups and 3 unknown MoA provided more than 90% reduction of adult D. citri over 24–68 days. Observable effects on nymphs were generally of shorter duration due to rapid maturation of flush. However, reduction of 76–100% nymphs or adults over 99–296 days was seen on young trees receiving drenches of the neonicotinoids imidacloprid, thiamethoxam or clothianidin (MoA 4A) and a novel anthranilic diamide, cyantraniliprole (MoA 28). Effective products identified for foliar sprays to control D. citri provide sufficient MoA groups for rotation to delay evolution of insecticide resistance by D. citri and other pests. However, cyantraniliprole is now the only available alternative for rotation with neonicotinoids in soil application to young trees. Sprays of up to eight of the most effective insecticides could be rotated over a year without repetition of any MoA and little or no recourse to neonicotinoids or cyantraniliprole, so important for protection of young trees. Other considerations effecting decisions of what and when to spray include prevalence of huanglongbing, pest pressure, pre-harvest intervals, overall budget, equipment availability, and conservation of beneficial arthropods. Examples of spray programs utilizing broad-spectrum and relatively selective insecticides are provided to improve vector management and may vary depending on individual or regional assessment of all factors.

Mathematical models are a powerful method to understand and control the spread of Huanglongbing

“…While many groves are being sprayed with insecticides to control psyllids and thus HLB (Grafton-Cardwell, Stelinski & Stansly, 2013), the range of methods for insecticide application across the US is large with differences in number of applications per year and the efficiency of the insecticide (Qureshi, Kostyk & Stansly, 2014; Rogers, 2008). We assess insecticide application efficiency through a process akin to global sensitivity—we vary the level of insecticide efficiency and the number of days spraying throughout the year over a wide range to capture the current state of play of insecticide application.…”

“…Multiple sprays in a year occur in most groves, with varying ranges of up to seven sprays (Stansly et al, 2014), monthly (Rogers, 2008), or up to 20 sprays per year (Spreen et al, 2006), using a variety of approved sprays that differ in effectiveness (Rogers, 2008); some sprays can have an average efficiency as low as 53% (Qureshi, Kostyk & Stansly, 2014). Although 60 days is unrealistic logistically in terms of potential insecticide strategies it allows us to investigate the effect of very aggressive control.…”

“…However, before controls can be implemented in the field they need to be tested for efficacy. There are presently tens if not hundreds of hypothetical interventions that could be tested, including: antibiotics (Zhang et al, 2014), pesticides (Qureshi, Kostyk & Stansly, 2014), biocontrol agents (Michaud, 2002), heat treatment (Hoffman et al, 2013), new tolerant or resistant tree stocks (Dutt et al, 2015), nutrient additions (Gottwald et al, 2012), tree removal (Gottwald, 2010), changes to tree spacing (Martini, Pelz-Stelinski & Stelinski, 2015), intercropping (Gottwald et al, 2014), and psyllid deterrents and barriers (Tisgratog et al, 2016; Tomaseto, Krugner & Lopes, 2016). Even more daunting are the different factorial combinations of interventions to test.…”

Susceptibility of Asian citrus psyllid, Diaphorina citri (Hemiptera: Liviidae), to the insecticide afidopyropen: a new and potent modulator of insect transient receptor potential channels

“…The management of HLB is currently accomplished by vector suppression. Therefore, D. citri is managed with multiple applications of insecticides, but there are a limited number of modes of action available per growing season (Baldessari et al 2010;GraftonCardwell et al 2013;Qureshi et al 2014;Yasui et al 1985).…”

Field Trial of Aqueous and Emulsion Preparations of Entomopathogenic Fungi Against the Asian Citrus Psyllid (Hemiptera: Liviidae) in a Lime Orchard in Mexico

“…Presently, effective eradication methods against the rapidly dispersing vector are unavailable (Bové 2006). Management of D. citri has been constrained to the use of chemical control (Yang et al 2006;Belasque et al 2010;Stansly et al 2013;Qureshi et al 2014). However, intensive use of pesticides has began to produce collateral effects that are noticed in resistance selection to insecticides in the vector (Yang et al 2006;Tiwari et al 2011), resurgence of controlled key pests, and outbreaks of secondary pests (Yang et al 2006;Monzó et al 2012).…”