Behavioral manipulation of Drosophila suzukii for pest control: high attraction to yeast enhances insecticide efficacy when applied on leaves.

BACKGROUND: The invasive pest, Drosophila suzukii attacks fresh soft-skinned fruit. Broad-spectrum insecticides are implemented for control but there is a need to reduce environmental risks and insecticide residues on fruits. Hanseniaspora uvarum is a yeast frequently found on ripe fruits and associated with D. suzukii. We aim to exploit the ecological association and attraction of D. suzukii to H. uvarum by developing an attract-and-kill strategy, with spray-application on canopy but not fruit. We therefore investigated D. suzukii attraction, egg-laying and mortality when exposed to insecticidal yeast-based formulations. RESULTS: Hanseniaspora uvarum strongly attracted D. suzukii when applied on leaves of grapevine, Vitis vinifera. Notably, this attractiveness was competitive to ripe grape berries that were susceptible to D. suzukii infestation. Moreover, adding H. uvarum enhanced the efficacy of insecticidal formulations against D. suzukii. Flies exposed to leaves treated with yeast-insecticide formulations showed higher mortality and laid a lower number of eggs compared to flies exposed to insecticide alone. In a wind tunnel, all treatments containing H. uvarum alone or in combination with insecticides, caused similar upwind flight and landing at the odor source, which provides evidence that the addition of insecticide did not reduce D. suzukii attraction to yeast. CONCLUSION: Hanseniaspora uvarum can be used to manipulate the behavior of D. suzukii by attracting flies to insecticide formulations. Yeast attraction is competitive to grape berries and improves insecticide effectiveness, suggesting that sprays covering canopy only, could reduce residues on fruit without compromising management efficacy.

Field and greenhouse application of an attract-and-kill formulation based on the yeast Hanseniaspora uvarum and the insecticide spinosad to control Drosophila suzukii in grapes.

BACKGROUND: The invasive insect Drosophila suzukii (Matsumura) is an important pest of several red grape varieties. The yeast Hanseniaspora uvarum (Niehaus), which is associated with D. suzukii, strongly attracts flies and stimulates them to feed on yeast-laden food. In the present study, a formulation based on H. uvarum culture with spinosad insecticide was applied to the foliage of vineyards and control of D. suzukii was compared to applying spinosad to the whole plant. After successful H. uvarum and insecticide application in the vineyard, we tested additional H. uvarum-based formulations with spinosad in a greenhouse to determine their capacity to control D. suzukii. RESULTS: Application of the H. uvarum-spinosad formulation at 36.4 g of spinosad per hectare reduced the D. suzukii field infestation at the same rate as applying 120 g of spinosad per hectare and prevented spinosad residues on grapes. Leaves treated with H. uvarum and spinosad in the field and transferred to a laboratory assay caused high mortality to flies and reduced the number of eggs laid on fruits. Formulations with spinosad applied in the greenhouse showed that both H. uvarum culture and the yeast cell-free supernatant of a centrifuged culture increased fly mortality and reduced the number of eggs laid compared to the unsprayed control. CONCLUSION: In comparison to typical spinosad spray applications, the use of H. uvarum in combination with spinosad as an attract-and-kill formulation against D. suzukii reduces pesticide residues on the fruits by targeting the treatment to the canopy and decreasing the amount of insecticide per hectare without compromising control efficacy.

Lethal and sublethal effects of insecticides on the survival and reproduction of Brevipalpus yothersi (Acari: Tenuipalpidae).

The overuse of insecticides to control vector insects such as Diaphorina citri Kuwayama in citrus groves has altered the population dynamics of pest mites. Among phytophagous mites, population outbreaks of citrus leprosis mite, Brevipalpus yothersi Baker, have been increasingly intense and frequent in Brazilian citrus groves. Despite the great importance of the B. yothersi mite for citrus production, the lethal and sublethal effects of insecticides on this mite have not yet been studied. Therefore, in this study, the effects of insecticides commonly used for D. citri control on B. yothersi mortality, reproduction, and instantaneous growth rate were assessed. For this, two experiments were carried out, one under controlled conditions and another in a greenhouse. The insecticides tested were beta-cyfluthrin, bifenthrin, buprofezin, chlorpyrifos, dimethoate, pyriproxyfen, and thiamethoxam at 0 (control), 0.0625, 0.125, 0.25, 0.5, 1, and twofold the recommended insecticide concentration for D. citri control. The pyriproxyfen insecticide provided high mortality of B. yothersi even at low concentrations. Furthermore, this insecticide negatively interfered with the reproduction of this mite. Beta-cyfluthrin, bifenthrin, buprofezin, chlorpyrifos, dimethoate, and thiamethoxam, in the tested concentrations, showed low impact on citrus leprosis mite. Regarding the reproduction of the mite, no significant increase in fecundity was observed on B. yothersi females exposed to insecticide residues, regardless of the concentration tested. Therefore, the application of these insecticides in the management of pest insects is unlikely to promote an increase in the citrus leprosis mite population.

Exploring the Efficacy and Mechanisms of a Crop Sterilant for Reducing Infestation by Spotted-Wing Drosophila (Diptera: Drosophilidae).

Vinegar flies (Diptera: Drosophilidae) are well known to be associated with yeasts, which provide important nutrients and emit attractive semiochemicals. Drosophila suzukii (Matsumura) has become a major pest of berries and cherries around the world, requiring intensive management to maintain fruit quality. Although insecticides remain a dominant control approach, disruption of fly-yeast-host interactions remains a promising avenue for reducing the economic impact of this pest. We conducted field and laboratory experiments to explore whether a crop sterilant (peroxyacetic acid and hydrogen peroxide) developed for disease control can affect D. suzukii. In 2 yr of field tests in highbush blueberries, we found significantly lower infestation by D. suzukii in plots treated with the crop sterilant, both alone and in a rotation program with zeta-cypermethrin. When shoots from treated plots were tested in no-choice bioassays, crop sterilant treatments did not affect adult mortality or oviposition, but they reduced infestation. To explore the mechanisms in the laboratory, we found that the crop sterilant did not affect adult mortality, nor oviposition on treated fruit under no-choice settings, but adult flies settled and oviposited less on treated fruit in choice settings. When the crop sterilant was applied to colonies of Hanseniaspora uvarum (Niehaus) (Saccharomycetales: Saccharomycodaceae) and Issatchenkia terricola (Van der Walt) (Saccharomycetales: Saccharomycetacea) yeasts that are attractive and provide nutrition to D. suzukii, there was a dose-dependent inhibition of their growth. We highlight the potential for microbial management as a component of integrated pest management programs and prioritize research needs to incorporate this approach into control programs.

Case Report: Nasal Myiasis in an Elderly Patient with Atrophic Rhinitis and Facial Sequelae of Leprosy.

We describe a case of nasal myiasis in an 89-year-old Brazilian patient affected by leprosy with severe nasal sequelae. An initial treatment comprising sinusectomy combined with nasal endoscopy removed more than 300 larvae, supplemented by systemic treatment using oral and topical ivermectin and levofloxacin. Infestation recurred after 2 months, was treated similarly, and resolved completely. The case could be attributed to severe nasal leprosy sequelae, with a lack of sneezing reflex, painless ulceration, atrophic rhinitis (ozena), and inability to clean the nose properly due to hand and nose impairment. This case illustrates the importance of long-term medical follow-up of patients with leprosy sequelae.

Intervention Packages for Early Visceral Leishmaniasis Case Detection and Sandfly Control in Bangladesh: A Comparative Analysis.

We compared the efficacy of three intervention packages for active case detection (ACD) of visceral leishmaniasis (VL)/post-kala-azar dermal leishmaniasis (PKDL) combined with sandfly control around an index case. The packages were 1) no kala-azar transmission activity involving indoor residual spraying (IRS) with deltamethrin, peri-domestic deployment of larvicide with temephos, and house-to-house search for cases; 2) fever camp (FC) plus durable wall lining (DWL) with deltamethrin; and 3) FC plus insecticide (deltamethrin) impregnated bed-nets (ITN) around an index case. Fever camp includes 1-day campaign at the village level to screen and diagnose VL, PKDL, leprosy, malaria, and tuberculosis among residents with chronic fever or skin disease. Efficacy was measured through yield of new cases, vector density reduction, and mortality at 1, 3, 6, 9, and 12 months following intervention. Fever camp + DWL was the most efficacious intervention package with 0.5 case detected per intervention, 79% reduction in vector density (incidence rate ratio [IRR] = 0.21, P = 0.010), and 95.1% (95% confidence interval: 93.4%, 96.8%) sandfly mortality at 12 months. No kala-azar transmission activity was efficacious for vector control (74% vector reduction, IRR = 0.26, P < 0.0001 at 9 months; and 84% sandfly mortality at 3 months), but not for case detection (0 case per intervention). Fever camp + ITN was efficacious in detection of VL/PKDL cases (0.43 case per intervention), but its efficacy for vector control was inconsistent. We recommend index case-based FC for ACD combined with DWL or IRS plus larvicide for sandfly control during the consolidation and maintenance phases of the VL elimination program of the Indian subcontinent.

Integrating Case Detection of Visceral Leishmaniasis and Other Febrile Illness with Vector Control in the Post-Elimination Phase in Nepal.

Nepal has completed the attack phase of visceral leishmaniasis (VL) elimination and now needs active case detection (ACD) and vector control methods that are suitable to the consolidation and maintenance phases. We evaluated different ACD approaches and vector control methods in Saptari district. We assessed 1) mobile teams deployed in villages with VL cases in 2015 to conduct combined camps for fever and skin lesions to detect VL/PKDL (post-kala-azar dermal leishmaniasis) and other infections; 2) an incentive approach by trained female community health volunteers (FCHVs) in villages with no VL cases in 2015. Both were followed by house-to-house visits. For vector control, four villages were randomly allocated to insecticide impregnation of bednets, insecticide wall painting, indoor residual spraying (IRS), and control. Sandfly density (by CDC light traps, The John W. Hock Company, USA) and mortality (World Health Organization cone bioassay) were assessed in randomly selected households. One VL, three tuberculosis, one leprosy, and one malaria cases were identified among 395 febrile cases attending the camps. Post-camp house-to-house screening involving 7,211 households identified 679 chronic fever and 461 skin lesion cases but no additional VL/PKDL. No VL/PKDL case was found by FCHVs. The point prevalence of chronic fever in camp and FCHV villages was 242 and 2 per 10,000 populations, respectively. Indoor residual spraying and bednet impregnation were effective for 1 month versus 12 months with insecticidal wall paint. Twelve-month sandfly mortality was 23%, 26%, and 80%, respectively, on IRS, bednet impregnation, and insecticide wall painting. In Nepal, fever camps and insecticidal wall paint prove to be alternative, sustainable strategies in the VL post-elimination program.

Interaction of spirodiclofen with insecticides for the control of Brevipalpus yothersi in citrus.

BACKGROUND: The mite Brevipalpus yothersi (Acari: Tenuipalpidae) is of great importance in citriculture because it is a vector of the disease citrus leprosis. The frequency of application of a combination of pesticides has increased because of an increase in the occurrence of economically important pests of citrus. However, the combined effect of acaricide and other insecticides targeting B. yothersi is unknown. The objective of this study was to evaluate the effect of a combination of spirodiclofen and other insecticides on the control of B. yothersi. RESULTS: Analysis using spirodiclofen alone resulted in 97.22% efficiency in the control of B. yothersi on day 7 after application. A combination of spirodiclofen with either phosmet or imidacloprid resulted in 55% and 59% efficiency, respectively. A reduction in the efficiency of mite control by up to 42% was observed when the mites were exposed to a combination of acaricide with other insecticides. CONCLUSIONS: Application of a combination of spirodiclofen with phosmet or imidacloprid compromises the efficiency of acaricide in the control of B. yothersi. © 2018 Society of Chemical Industry.

Feasibility of a combined camp approach for vector control together with active case detection of visceral leishmaniasis, post kala-azar dermal leishmaniasis, tuberculosis, leprosy and malaria in Bangladesh, India and Nepal: an exploratory study.

BACKGROUND: We assessed the feasibility and results of active case detection (ACD) of visceral leishmaniasis (VL), post kala-azar dermal leishmaniasis (PKDL) and other febrile diseases as well as of bednet impregnation for vector control. METHODS: Fever camps were organized and analyzed in twelve VL endemic villages in Bangladesh, India, and Nepal. VL, PKDL, tuberculosis, malaria and leprosy were screened among the febrile patients attending the camps, and existing bednets were impregnated with a slow release insecticide. RESULTS: Among the camp attendees one new VL case and two PKDL cases were detected in Bangladesh and one VL case in Nepal. Among suspected tuberculosis cases two were positive in India but none in the other countries. In India, two leprosy cases were found. No malaria cases were detected. Bednet impregnation coverage during fever camps was more than 80% in the three countries. Bednet impregnation led to a reduction of sandfly densities after 2 weeks by 86% and 32%, and after 4 weeks by 95% and 12% in India and Nepal respectively. The additional costs for the control programmes seem to be reasonable. CONCLUSION: It is feasible to combine ACD camps for VL and PKDL along with other febrile diseases, and vector control with bednet impregnation.

Pediculosis capitis: an update.

Head louse infestation, or pediculosis capitis, caused by Pediculus humanus var. capitis, is a common health concern in pediatric age group. An itching of the scalp is the chief symptom, whereas presence of viable nits confirms the diagnosis of head louse infestation. Secondary bacterial infection with impetignization with cervical and occipital lymphadenopathy can complicate the clinical scenario with physician misdiagnosing pediculosis to a primary bacterial infection. Screening and treatment of all close contacts is necessary for an adequate management of pediculosis. Medical management of head louse infestation requires proper application of topical pediculicidal agents', chiefly permethrin lotion and wet combing with a fine toothcomb. Severe cases with high parasitic load justify the use of either oral cotrimoxazole or Ivermectin. Other described technique involves a single application of hot air for 30 minutes. Radical but culturally unacceptable method would be shaving of scalp in resistant cases. Environmental fogging with insecticides is neither necessary nor recommended.

Resistência de Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) a acaricidas inibidores da respiração celular em citros: resistência cruzada e custo adaptativo / Resistance of Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) to acaricides that inhibit cellular respiration in citrus: cross-resistance and fitness cost

Acaricidas inibidores da respiração celular são importantes para o controle de Brevipalpus phoenicis (Geijskes) na cultura dos citros no Brasil. Foram conduzidos estudos para avaliar: (a) a variabilidade na suscetibilidade de populações de B. phoenicis coletadas em pomares de citros para cihexatim, azociclotim, propargite e enxofre; (b) relações de resistência cruzada entre propargite e os acaricidas azociclotim, cihexatim, dinocape, piridabem e enxofre; e (c) o custo adaptativo associado à resistência de B. phoenicis a propargite em condições de laboratório. O método de bioensaio adotado foi o contato residual. A suscetibilidade foi estimada com concentrações diagnósticas baseadas na CL95 de cada acaricida. A resistência cruzada foi avaliada pela caracterização da curva de concentração-mortalidade das linhagens suscetível (S) e resistente a propargite (Propargite-R). O custo adaptativo foi avaliado mediante comparação de parâmetros biológicos das linhagens S e Propargite-R em frutos de laranja a 25 ± 1°C e fotofase de 14h. Diferenças significativas na sobrevivência de B. phoenicis foram verificadas aos acaricidas cihexatim (de 16,3 por cento a 80,5 por cento), azociclotim (de 3,0 por cento a 15,0 por cento), propargite (de 1,0 por cento a 71,6 por cento) e enxofre (de 9,0 por cento a 82,6 por cento). Baixa intensidade de resistência cruzada foi verificada entre propargite e os acaricidas azociclotim (1,8 vezes), cihexatim (4,6 vezes), dinocape (3,5 vezes) e piridabem (3,5 vezes). Por outro lado, a intensidade de resistência cruzada a enxofre (> 111 vezes) foi bastante alta. Não foi verificada presença de custo adaptativo associado à resistência de B. phoenicis a propargite. Portanto, o uso desses acaricidas também deve ser feito de maneira criteriosa no manejo da resistência de B. phoenicis a acaricidas.

Acaricides that inhibit cellular respiration play an important role in the control of Brevipalpus phoenicis (Geijskes) in citrus groves in Brazil. Studies were conducted to evaluate: (a) the variability in the susceptibility among B. phoenicis populations collected from citrus groves to cyhexatin, azocyclotin, propargite and sulphur; (b) cross-resistance relationships between propargite and azocyclotin, cyhexatin, dinocap, pyridaben and sulphur; and (c) the fitness cost associated with propargite resistance in B. phoenicis under laboratory conditions. A residual-type contact bioassay was used to characterize the susceptibility. The susceptibility was estimated with diagnostic concentrations based LC95 of each acaricide. The cross-resistance was evaluated by characterizing the concentration-mortality responses of susceptible (S) and propargite-resistant (Propargite-R) strains. The fitness cost was evaluated by measuring the biological parameters of S and Propargite-R strains on citrus fruits at 25 ± 1°C and fotophase of 14h. Significant differences in the susceptibility of B. phoenicis were detected at diagnostic concentration of cyhexatin (survivorship from 16.3 percent to 80.5 percent), azocyclotin (from 3.0 percent to 15.0 percent), propargite (from 1.0 percent a 71.6 percent) and sulphur (from 9.0 percent to 82.6 percent). A low intensity of cross-resistance was detected between propargite and the acaricides azocyclotin (1.8-fold), cyhexatin (4.6-fold), dinocap (3.5-fold) and pyridaben (3.5-fold). On the other hand, the intensity of cross-resistance to sulphur (> 111-fold) was very high. There was no fitness cost associated with B. phoenicis resistance to propargite, based on biological parameters evaluated. Therefore, the use of these acaricides should also be done very carefully in resistance management of B. phoenicis to acaricides.

Estabilidade da resistência de Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) a hexythiazox em pomares de citros / Stability of Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) resistance to hexythiazox in citrus groves

O ácaro-da-leprose, Brevipalpus phoenicis (Geijskes), é uma das principais pragas da cultura dos citros (Citrus spp.), por ser o transmissor do vírus que causa a leprose dos citros. O acaricida hexythiazox tem sido bastante utilizado no controle de B. phoenicis em pomares de citros. A resistência do ácaro a hexythiazox já foi detectada em altas freqüências em algumas localidades. Para a implementação de um programa de manejo da resistência, foram realizados estudos para entender a estabilidade da resistência de B. phoenicis a hexythiazox mediante 1) a comparação da biologia das linhagens suscetível (S) e resistente (R) ao hexythiazox em condições de laboratório e 2) a avaliação da dinâmica da resistência a hexythiazox em talhões de citros com baixa (< 20 por cento) e alta (> 60 por cento) freqüência de resistência, por dois anos. Estimativas da freqüência de resistência foram realizadas com bioensaio de contato direto sobre ovos, utilizando-se a concentração discriminatória de 18 mg de hexythiazox/L de água. Não foram verificadas diferenças significativas entre as linhagens S e R, quanto aos parâmetros biológicos avaliados para a confecção das tabelas de vida de fertilidade. No entanto, a resistência de B. phoenicis a hexythiazox foi instável em condições de campo, isto é, foram verificadas reduções significativas na freqüência de resistência na ausência de pressão de seleção, tanto em talhões de citros com baixa freqüência como em talhões com alta freqüência de resistência. Portanto, a instabilidade da resistência de B. phoenicis a hexythiazox pode ser explorada em programas de manejo da resistência.

The false spider mite, Brevipalpus phoenicis (Geijskes), is one the most important pests of the citrus groves and transmits the citrus leprosis virus. The acaricide hexythiazox has been widely used for controlling B. phoenicis in citrus groves. The resistance of this species to hexythiazox has already been detected at high frequencies at some locations. In order to implement a resistance management program, studies were undertaken to understand the stability of the resistance of B. phoenicis to hexythiazox by 1) comparing the life-history of susceptible (S) and resistant (R) strains under laboratory conditions, and 2) evaluating the dynamics of hexythiazox resistance in citrus field plots with low (< 20 percent) and high (> 60 percent) frequency of resistance, during two years. The frequencies of resistance were estimated with direct contact bioassays on eggs with discriminating concentration of 18 mg of hexythiazox/L of water. There were no significant differences between S and R strains, based on biological parameters evaluated to build fertility life tables. However, the resistance of B. phoenicis to hexythiazox was unstable under field conditions; that is, significant reductions in the frequency of resistance were observed in the absence of selection pressure, either in citrus field plots with low or high frequency of resistance. Therefore, the instability of B. phoenicis resistance to hexythiazox can be exploited in resistance management programs.

Comparison of the efficacy of topical 1% lindane vs 5% permethrin in scabies: a randomized, double-blind study.

BACKGROUND: Permethrin, a pyrethroid insecticide, is not yet available in Iran and may be a useful substitute for the control of scabies in Iran. AIM: To compare the efficacy of topical lindane with topical permethrin in the treatment of scabies in a population in Iran. METHODS: In a double-blind, randomized study, all consecutive patients with scabies were randomized into two groups. One group and their family contacts received 1% lindane cream, and the other group and their family contacts were treated with topical 5% permethrin cream. Subsequently, patients were followed up at 2- and 4-week post-treatment. RESULTS: Of the 99 patients enrolled in the study, 47 patients received 1% lindane cream, and 52 patients were treated topically with 5% permethrin cream. Permethrin provided an improvement rate of 84.6% after two weeks, whereas lindane was effective only in 48.9% of patients. CONCLUSION: Permethrin (5%) cream was found to be significantly more effective in the treatment of scabies in comparison with lindane in this study, and it seems that it could be an alternative treatment.

[Stability of Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) resistance to hexythiazox in citrus groves]. / Estabilidade da resistência de Brevipalpus phoenicis (Geijskes) (Acari: Tenuipalpidae) a hexythiazox em pomares de citros.

The false spider mite, Brevipalpus phoenicis (Geijskes), is one the most important pests of the citrus groves and transmits the citrus leprosis virus. The acaricide hexythiazox has been widely used for controlling B. phoenicis in citrus groves. The resistance of this species to hexythiazox has already been detected at high frequencies at some locations. In order to implement a resistance management program, studies were undertaken to understand the stability of the resistance of B. phoenicis to hexythiazox by 1) comparing the life-history of susceptible (S) and resistant (R) strains under laboratory conditions, and 2) evaluating the dynamics of hexythiazox resistance in citrus field plots with low (< 20%) and high (> 60%) frequency of resistance, during two years. The frequencies of resistance were estimated with direct contact bioassays on eggs with discriminating concentration of 18 mg of hexythiazox/L of water. There were no significant differences between S and R strains, based on biological parameters evaluated to build fertility life tables. However, the resistance of B. phoenicis to hexythiazox was unstable under field conditions; that is, significant reductions in the frequency of resistance were observed in the absence of selection pressure, either in citrus field plots with low or high frequency of resistance. Therefore, the instability of B. phoenicis resistance to hexythiazox can be exploited in resistance management programs.