New data on the distribution and abundance of Dendrolimus sibiricus (Tshetverikov, 1908) (Lepidoptera: Lasiocampidae) in the Komi Republic.

The Siberian silkworm (Dendrolimus sibiricus Tschetv.) is a defoliator pest that poses a significant threat to coniferous forest stands. Over the past decades, several large outbreaks of this species have occurred in Siberia (Russia), which has led to changes in forest ecosystems and an increase of expenses involved in reforestation. Adults capture new territories in the process of migration, therefore, a set of measures is needed to register the number and prevent further dispersal of the moth. One of methods of trapping is glue traps with synthetic pheromone. 16 district forestries located in the middle taiga subzone, with a total area of 151 850 hectares, were surveyed as a part of the phytosanitary monitoring of the Siberian silkworm in the Komi Republic (Russia). Analysis of 773 pheromone traps showed 414 males of the target species that were identified by their genitals. The highest indicators of catchability were found in three district forestries. Taking into account the results obtained, it was proposed to continue the monitoring using the pheromone traps, to survey more northern forest districts and to carry out subsequent searches for preimaginal stages of the silkworm in the forest districts of Priluzsky district. The study will be useful for predicting the further spread of the silkworm and for developing optimal containment and control of the pest.

Development of Monitoring and Mating Disruption Against the Chilean Leafroller Proeulia auraria (Lepidoptera: Tortricidae) in Orchards

The leafroller Proeulia auraria (Clarke) (Lepidoptera: Tortricidae) is a native, polyphagous, and growing pest of several fruit crops in Chile; it also has quarantine importance to several markets, thus tools for management are needed. Using synthetic pheromone compounds, we conducted field trials to optimize the blend for monitoring, and to determine the activity period of rubber septa aged under field conditions. We concluded that septa loaded with 200 μg of E11-14:OAc + 60 μg E11-14:OH allowed for efficient trap captures for up to 10 weeks. Using this blend, we studied the phenology of adult males in vineyards, apple, and blueberry orchards, identifying two long flight cycles per season, lasting from September to May and suggesting 2–3 generations during the season. No or low adult activity was observed during January and between late May and late August. Furthermore, mating disruption (MD) field trials showed that application of 250 pheromone point sources using the dispenser wax matrix SPLAT (Specialized Pheromone and Lure Application Technology, 10.5% pheromone) with a total of 78 g/ha of the blend described above resulted in trap shutdown immediately after application, and mating disruption >99% in all orchards for at least 5 months. We concluded that MD is feasible for P. auraria, needing now the development of a commercial product and the strategy (and protocols) necessary to control this pest in conventional and organic orchards in Chile. As far as we know, this is the first report on MD development against a South American tortricid pest.

Diel Rhythmicity of Field Responses to Synthetic Pheromone Lures in the Pine Sawyer Monochamus saltuarius

The pine wood nematode (PWN), Bursaphelenchus xylophilus, causes lethal pine wilt disease (PWD) in Asia and Europe and has become a serious threat to global pine forest ecosystems. In Korea, Monochamus saltuarius transmits PWN not only to Pinus densiflora, but also to Pinus koraiensis, which is widely distributed across eastern Asia. The diel rhythmicity of M. saltuarius in response to its aggregation pheromone was studied with the aim of providing reliable data for the prevention of PWD and control of Monochamus spp. Using a spray dispenser controlled with an electronic timer, M. saltuarius pheromone and attractants (PA) were sprayed to determine the diel rhythm of the response to PA. The spraying period was divided into four time periods: 05:00–11:00 (time period A), 11:00–17:00 (time period B), 17:00–23:00 (time period C), and 23:00–05:00 (time period D). The largest number of M. saltuarius was caught in time period B, followed by A, C, and D. It could be concluded that the flight activity of M. saltuarius in response to PA was diurnal. The results of this study improve the understanding of the behavioral biology of M. saltuarius, allowing for the development of pest management strategies to prevent the spread of PWN and control its vector.

Modelling Sand Fly Lutzomyia longipalpis Attraction to Host Odour: Synthetic Sex-Aggregation Pheromone Dominates the Response

Zoontic visceral leishmaniasis (ZVL) due to Leishmania infantum is a potentially fatal protozoan parasitic disease of humans and dogs. In the Americas, dogs are the reservoir and the sand fly, Lutzomyia longipalpis, the principal vector. A synthetic version of the male sand fly produced sex-aggregation pheromone attracts both female and male conspecifics to co-located insecticide, reducing both reservoir infection and vector abundance. However the effect of the synthetic pheromone on the vector’s “choice“ of host (human, animal reservoir, or dead-end host) for blood feeding in the presence of the pheromone is less well understood. In this study, we developed a modelling framework to allow us to predict the relative attractiveness of the synthetic pheromone and potential alterations in host choice. Our analysis indicates that the synthetic pheromone can attract 53% (95% CIs: 39%–86%) of host-seeking female Lu. longipalpis and thus it out-competes competing host odours. Importantly, the results suggest that the synthetic pheromone can lure vectors away from humans and dogs, such that when co-located with insecticide, it provides protection against transmission leading to human and canine ZVL.

Community deployment of a synthetic pheromone of the sand fly Lutzomyia longipalpis co-located with insecticide reduces vector abundance in treated and neighbouring untreated houses: Implications for control of Leishmania infantum

Background The rising incidence of visceral leishmaniasis due to Leishmania infantum requires novel methods to control transmission by the sand fly vector. Indoor residual spraying of insecticide (IRS) against these largely exophilic / exophagic vectors may not be the most effective method. A synthetic copy of the male sex-aggregation pheromone of the key vector species Lutzomyia longipalpis in the Americas, was co-located with residual pyrethroid insecticide, and tested for its effects on vector abundance, hence potential transmission, in a Brazilian community study. Methods Houses within eight defined semi-urban blocks in an endemic municipality in Brazil were randomised to synthetic pheromone + insecticide or to placebo treatments. A similar number of houses located >100m from each block were placebo treated and considered as “True Controls” (thus, analysed as three trial arms). Insecticide was sprayed on a 2.6m2 surface area of the property boundary or outbuilding wall, co-located within one metre of 50mg synthetic pheromone in controlled-release dispensers. Vector numbers captured in nearby CDC light traps were recorded at monthly intervals over 3 months post intervention. Recruited sentinel houses under True Control and pheromone + insecticide treatments were similarly monitored at 7–9 day intervals. The intervention effects were estimated by mixed effects negative binomial models compared to the True Control group. Results Dose-response field assays using 50mg of the synthetic pheromone captured a mean 4.8 (95% C.L.: 3.91, 5.80) to 6.3 (95% C.L.: 3.24, 12.11) times more vectors (female Lu. longipalpis) than using 10mg of synthetic pheromone. The intervention reduced household female vector abundance by 59% (C.L.: 48.7, 66.7%) (IRR = 0.41) estimated by the cross-sectional community study, and by 70% (C.L.: 56.7%, 78.8%) estimated by the longitudinal sentinel study. Similar reductions in male Lu. longipalpis were observed. Beneficial spill-over intervention effects were also observed at nearby untreated households with a mean reduction of 24% (95% C.L.: 0.050%, 39.8%) in female vectors. The spill-over effect in untreated houses was 44% (95% C.L.: 29.7%, 56.1%) as effective as the intervention in pheromone-treated houses. Ownership of chickens increased the intervention effects in both treated and untreated houses, attributed to the suspected synergistic attraction of the synthetic pheromone and chicken kairomones. The variation in IRR between study blocks was not associated with inter-household distances, household densities, or coverage (proportion of total households treated). Conclusions The study confirms the entomological efficacy of the lure-and-kill method to reduce the abundance of this important sand fly vector in treated and untreated homesteads. The outcomes were achieved by low coverage and using only 1–2% of the quantity of insecticide as normally required for IRS, indicating the potential cost-effectiveness of this method. Implications for programmatic deployment of this vector control method are discussed.

Octadecanal as the Male-Produced Aggregation Pheromone of the Coconut Weevil, Amerrhinus ynca (Coleoptera: Curculionidae)

The beetle Amerrhinus ynca Sahlberg, 1823 (Coleoptera: Curculionidae) causes damage to several species of the Arecaceae family. The larvae of this palm weevil damage palm trees by causing perforations in the leaf rachis, obstructing the flow of nutrients to the plant. To date, are no registered insecticides for the control of A. ynca. An efficient control strategy would be the use of synthetic pheromones of this beetle for integrated pest management tactics. In this work, the aggregation pheromone of A. ynca was identified from adults collected as larvae and pupae from the rachis of coconut palm. The volatile compounds produced by A. ynca were collected via headspace aeration of adult beetles, and the identification of the pheromone was performed with gas chromatography coupled to mass spectrometry (GC-MS), GC-Fourier transform infrared spectroscopy (GC-FTIR) and GC-electroantenographic detector (GC-EAD). Dual-choice olfactometry experiments were performed to evaluate the bioactivity of the synthetic pheromone. GC analyses showed the presence of a male-specific compound that was identified as octadecanal. In GC-EAD analyses, synthetic octadecanal elicited responses of A. ynca female antennae. Behavioral bioassays showed attractiveness of synthetic compound for males and females, indicating octadecanal as the aggregation pheromone of A. ynca.

One Decade’s Research Efforts in Hungary to Develop a Bisexual Lure for the Cotton Bollworm Helicoverpa armigera Hübner

The addition of synthetic (E)-anethol to the known attractant phenylacetaldehyde synergized attraction of the cotton bollworm Helicoverpa armigera, the blend invariably catching 4 to 6 times more than phenylacetaldehyde on its own. Highest catches were recorded by the 1:1-3:1 blends. The addition of salicyl aldehyde, ±linalool, (R)-(+)-limonene, 2-methoxybenzyl alcohol and 4-methoxybenzyl alcohol (compounds described earlier in the literature as co-attractants for H. armigera), increased catches when added to phenylacetaldehyde. However, the addition of these compounds did not increase catches of the (E)-anethol+pheny- lacetaldehyde blend. When directly compared with performance of the synthetic pheromone, the (E)-anethol +phenylacetaldehyde blend caught an average of 27% of the catch in pheromone baited traps. On an average 79% of moths caught in traps with the (E)-anethol+phenylacetaldehyde blend were females, while traps with pheromone caught only males. The (E)-anethol+phenylacetaldehyde blend described in this study may form the basis for the development of an efficient bisexual lure for H. armigera AFTER further optimization.

Insecticide-impregnated netting as a potential surface treatment: an alternative to insecticide spraying for control of the leishmaniasis vector Lutzomyia longipalpis (Diptera: Psychodidae)?

Background: The sand fly, Lutzomyia longipalpis, is the main vector of Leishmania infantum in Brazil. A previous laboratory study showed that covering surfaces with insecticide-impregnated netting may provide an alternative method for killing sand flies. Synthetic male Lu. longipalpis sex/aggregation pheromone co-located with micro-encapsulated l-cyhalothrin demonstrated the potential of “lure-and-kill” to significantly reduce canine infection and sand fly densities. In this study we were interested to determine if insecticide impregnated netting could replace sprayed insecticide for Lu. longipalpis control.Methods: We placed synthetic pheromone in experimental and real chicken sheds treated with a 1m2 surface of either sprayed insecticide or insecticide-impregnated netting. Two experiments in experimental chicken sheds were carried out to determine the effect of the insecticide treatments on Lu. longipalpis over 1-week and 16-week periods. We counted the number of Lu. longipalpis collected overnight and dead at 24 hours. Two longitudinal intervention studies were carried in real chicken sheds and compared the numbers of Lu. longipalpis (collected and dead at 24h) before adding the intervention (either the netting or sprayed insecticide treatments) with the numbers collected 24h after the intervention. Results: In the first experiment all flies caught in the spray treated experimental chicken sheds were dead at 24 hours and in netting treated sheds 97% of females and 88% of males were dead at 24 hours (257 vs 225, Wilcoxon Signed Ranks Test P=0.043). The netting and spray treated traps were equally effective at killing both female and male Lu. longipalpis over the first 8-weeks however after 16-weeks both treatments killed a significantly lower proportion of females (64%vs 96%; P=0.000) and males 89%vs 100%; P=0.000) compared to the beginning. In the first of the longitudinal studies in real chicken sheds only the netting intervention significantly increased the proportion of females dead after 24h (60%vs81%; P=0.042). The subsequent study showed that both netting and spraying treatments had similarly significant impacts on the proportion of females dead after 24h (netting: 60%vs80%: P=0.0194 and spraying: 43%vs72%: P=0.0004).Conclusions: The netting and spray insecticide interventions (with synthetic sex/aggregation pheromone) have similar impacts on the Lu. longipalpis population.