Predição espacial do ácaro‑vermelho‑das‑palmeiras no Brasil sob cenários atual e futuros de mudanças climáticas

The objective of this work was to predict the spatial distribution of the red palm mite, Raoiella indica (Acari: Tenuipalpidae), in Brazil under current and future climate change scenarios. A mapping method of species distribution based on the geographic information system (GIS) was used. The maps were constructed taking into account ranges of favorability for temperature and relative humidity. Favorability levels were defined considering the available information on pest biology and population dynamics. To characterize the current climatic conditions, information was referenced to the climate normal from 1961 to 1990. Future scenarios for the models were the A2 and B1 gas emission scenarios from the Intergovernmental Panel on Climate Change, focusing on the periods of 2011–2040, 2041–2070, and 2071–2100. The constructed maps showed that, for the reference period, Brazil presents extensive areas with favorable or very favorable conditions for the establishment of red palm mite populations. An increasing favorability was observed for future scenarios when compared with the reference period, indicating that the pest impact will worsen if it is already widely spread and causing damage in the country. Under current and future climate scenarios, most of the favorable and very favorable areas for red palm mite are in northeastern Brazil.O objetivo deste trabalho foi predizer a distribuição espacial do ácaro‑vermelho‑das‑palmeiras, Raoiella indica (Acari: Tenuipalpidae), no Brasil, em cenários atual e futuros de mudanças climáticas. Foi utilizado um método de mapeamento de distribuição de espécies baseado no sistema de informação geográfica (SIG). Os mapas foram construídos considerando faixas de favorabilidade de temperatura e umidade relativa. Os níveis de favorabilidade foram definidos a partir da informação disponível sobre a biologia e a dinâmica populacional da praga. Para caracterizar as condições climáticas atuais, informações foram referenciadas para a normal climatológica de 1961 a 1990. Os cenários futuros para os modelos foram os cenários A2 e B1 de emissões de gases, do Painel Intergovernamental sobre Mudanças Climáticas, focalizados nos períodos de 2011–2040, 2041–2070 e 2071–2100. Os mapas construídos mostraram que, para o período de referência, o Brasil apresenta extensas áreas com condições favoráveis ou muito favoráveis para o estabelecimento de populações do ácaro‑vermelho‑das‑palmeiras. Observou-se aumento de favorabilidade para os cenários futuros quando comparados ao período de referência, o que indica que o impacto da praga se agravará, caso esta já esteja amplamente disseminada e causando danos no País. Nos cenários atual e futuros de mudanças climáticas, a maior parte das áreas favoráveis e muito favoráveis para o ácaro‑vermelho‑das‑palmeiras está no Nordeste do Brasil

Evaluating damage in the perianth: a new diagrammatic scale to estimate population level of Aceria guerreronis Keifer (Acari: Eriophyidae) in coconut fruits

The coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), is one of the main pests of the coconut crop by attacking the fruits. Colonies can reach 10,000 mites/fruit at high infestation. A diagrammatic scale (Galvão scale) has been developed and tested by Brazilian researchers to estimate the number of mites/fruit by determining the percentage of necrotic area of the fruit surface. Our objective was to develop and validate a new diagrammatic scale based on the percentage of the damaged perimeter of the fruit at the base of the perianth, in order to facilitate and improve the quantification of A. guerreronis per fruit. Fruits were collected in an urban coconut plantation in Ilhéus, Bahia, Brazil. For the development of the new diagrammatic scale, it was calculated the percentage of the damaged perimeter on 50 fruits with different damage levels. To analyze the relationship between the damage and population levels of A. guerreronis on the fruits, we compared the two scales by testing them both on 470 fruits. The new diagrammatic scale recorded nine damage levels, 1, 2, 4, 8, 16, 32, 48, 70 and 100%. To validate our new diagrammatic scale, the damage level in each fruit was estimated by 10 inexperienced evaluators, with and without the aid of the scale. The accuracy and precision of each evaluator were determined through linear regression between observed and estimated damage. With or without or the use of the scale, 5 of 10 evaluators overestimated or underestimated the damage level and were imprecise and inaccurate. This showed that the scale did not provide improvements in the levels of accuracy and precision of the evaluators. The relationship between infestation and damage levels showed high accuracy for both scales in the regression analysis (R²= 96% and R²= 98%). The population peak of A. guerreronis by the new diagrammatic scale occurred at 32% of damage level and for the Galvão scale it occurred at 8% of damage level. Although the new diagrammatic scale has not promoted improvements in damage estimates, it presented high precision in the relationship between infestation and damage levels

Pesticides and passive dispersal: acaricide‐ and starvation‐induced take‐off of the predatory mite Neoseiulus baraki

An understanding of the causes and consequences of dispersal is vital for managing populations. Environmental contaminants, such as pesticides, provide potential environmental context‐dependent stimuli for dispersal of targeted and non‐targeted species, which may occur not only for active but also for passive dispersal, although such a possibility is frequently neglected. Here, we assessed the potential of food deprivation and acaricides to interfere with the take‐off for passive (wind) dispersal of the predatory mite Neoseiulus baraki. Wind tunnel bioassays indicated that starvation favoured the take‐off for wind dispersal by the mite predator, which also varied with wind velocity, and dispersal increased at higher velocities within the 1–7 (m s−1) range tested. For the acaricides tested, particularly the biopesticide azadirachtin but also abamectin and fenpyroximate, the rate of predator take‐off for dispersal increased, and further increased with wind velocity up to 7 m/s. Such responses were associated with changes in the predator behavioural preparation for wind‐mediated passive dispersal, with a greater incidence of the standing posture that permitted take‐off. The rate of take‐off for passive dispersal by N. baraki increased with food deprivation and exposure to the residues of agricultural acaricides. Azadirachtin exposure resulted in a particularly strong response, although abamectin and fenpyroximate also stimulated dispersal

Evaluating damage in the perianth: a new diagrammatic scale to estimate population level of Aceria guerreronis Keifer (Acari: Eriophyidae) in coconut fruits

The coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), is one of the main pests of the coconut crop by attacking the fruits. Colonies can reach 10,000 mites/fruit at high infestation. A diagrammatic scale (Galvão scale) has been developed and tested by Brazilian researchers to estimate the number of mites/fruit by determining the percentage of necrotic area of the fruit surface. Our objective was to develop and validate a new diagrammatic scale based on the percentage of the damaged perimeter of the fruit at the base of the perianth, in order to facilitate and improve the quantification of A. guerreronis per fruit. Fruits were collected in an urban coconut plantation in Ilhéus, Bahia, Brazil. For the development of the new diagrammatic scale, it was calculated the percentage of the damaged perimeter on 50 fruits with different damage levels. To analyze the relationship between the damage and population levels of A. guerreronis on the fruits, we compared the two scales by testing them both on 470 fruits. The new diagrammatic scale recorded nine damage levels, 1, 2, 4, 8, 16, 32, 48, 70 and 100%. To validate our new diagrammatic scale, the damage level in each fruit was estimated by 10 inexperienced evaluators, with and without the aid of the scale. The accuracy and precision of each evaluator were determined through linear regression between observed and estimated damage. With or without or the use of the scale, 5 of 10 evaluators overestimated or underestimated the damage level and were imprecise and inaccurate. This showed that the scale did not provide improvements in the levels of accuracy and precision of the evaluators. The relationship between infestation and damage levels showed high accuracy for both scales in the regression analysis (R²= 96% and R²= 98%). The population peak of A. guerreronis by the new diagrammatic scale occurred at 32% of damage level and for the Galvão scale it occurred at 8% of damage level. Although the new diagrammatic scale has not promoted improvements in damage estimates, it presented high precision in the relationship between infestation and damage levels

Evaluating damage in the perianth: a new diagrammatic scale to estimate population level of Aceria guerreronis Keifer (Acari: Eriophyidae) in coconut fruits

The coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae), is one of the main pests of the coconut crop by attacking the fruits. Colonies can reach 10,000 mites/fruit at high infestation. A diagrammatic scale (Galvão scale) has been developed and tested by Brazilian researchers to estimate the number of mites/fruit by determining the percentage of necrotic area of the fruit surface. Our objective was to develop and validate a new diagrammatic scale based on the percentage of the damaged perimeter of the fruit at the base of the perianth, in order to facilitate and improve the quantification of A. guerreronis per fruit. Fruits were collected in an urban coconut plantation in Ilhéus, Bahia, Brazil. For the development of the new diagrammatic scale, it was calculated the percentage of the damaged perimeter on 50 fruits with different damage levels. To analyze the relationship between the damage and population levels of A. guerreronis on the fruits, we compared the two scales by testing them both on 470 fruits. The new diagrammatic scale recorded nine damage levels, 1, 2, 4, 8, 16, 32, 48, 70 and 100%. To validate our new diagrammatic scale, the damage level in each fruit was estimated by 10 inexperienced evaluators, with and without the aid of the scale. The accuracy and precision of each evaluator were determined through linear regression between observed and estimated damage. With or without or the use of the scale, 5 of 10 evaluators overestimated or underestimated the damage level and were imprecise and inaccurate. This showed that the scale did not provide improvements in the levels of accuracy and precision of the evaluators. The relationship between infestation and damage levels showed high accuracy for both scales in the regression analysis (R²= 96% and R²= 98%). The population peak of A. guerreronis by the new diagrammatic scale occurred at 32% of damage level and for the Galvão scale it occurred at 8% of damage level. Although the new diagrammatic scale has not promoted improvements in damage estimates, it presented high precision in the relationship between infestation and damage levels