Biological Control Of Pest Mites Research Articles

Herbicides Harm Key Orchard Predatory Mites.

The phytoseiid mites Galendromus occidentalis and Amblydromella caudiglans are critical for conservation biological control of pest mites in Washington State, U.S.A. apples. While the non-target effects of insecticides on phytoseiids are well described, research on herbicide effects is limited. Using laboratory bioassays, we examined lethal (female mortality) and sublethal (fecundity, egg hatch, larval survival) effects of seven herbicides and five adjuvants on A. caudiglans and G. occidentalis. The effects of mixing herbicides with recommended adjuvants were also tested to determine if the addition of an adjuvant increased herbicide toxicity. Glufosinate was the least selective herbicide tested, causing 100% mortality in both species. Paraquat caused 100% mortality in A. caudiglans and 56% mortality in G. occidentalis. Sublethal effects were significant for both species when exposed to oxyfluorfen. Adjuvants did not cause non-target effects in A. caudiglans. The non-ionic surfactant and methylated seed oil increased mortality and decreased reproduction in G. occidentalis. The high toxicity of glufosinate and paraquat for both predators is concerning; these are the primary "burn down" herbicide alternatives to glyphosate, which is decreasing in use due to consumer toxicity concerns. Field studies are needed to determine the extent to which herbicides disrupt orchard biological control, focusing on glufosinate, paraquat, and oxyfluorfen. Consumer preferences will need to be balanced with natural enemy conservation.

Potential worldwide distributions of Neoseiulus californicus and Neoseiulus idaeus (Acari: Phytoseiidae) determined by climatic modelling

ABSTRACT Predatory mites belonging to the family Phytoseiidae are the main agents used globally for the biological control of pest mites, especially predators of the genus Neoseiulus, particularly Neoseiulus californicus (McGregor) and Neoseiulus idaeus (Denmark & Muma). A major target is the ubiquitous mite Tetranychus urticae (Koch). A major factor limiting the effectiveness of natural enemies in biological control programmes is unfavourable climatic conditions at the release site. This study aimed to determine the climatic envelopes of N. californicus and N. idaeus to predict the geographical areas with the highest climatic suitability of each species where its efficacy as a biological control agent would be maximized. Site occurrence data and the associated environmental variables were obtained from pre-existing spatial information found in online databases. These data were analysed using the MaxEnt software to map the geographic areas worldwide most suitable for each species. The climate suitability for N. californicus was especially limited by conditions of high temperature, while limiting factors for N. idaeus were annual variation in temperatures and low annual precipitation. Suitable areas for N. californicus were observed in all five continents, concentrated in latitudes close to the tropics of Cancer and Capricorn. In relation to N. idaeus, suitable areas were observed on four continents and are concentrated in countries close to the Equator, particularly those in the southern hemisphere. N. californicus and N. idaeus have distinct climate suitability areas. The results may be helpful for selecting the predator species for introduction.

Potential predation and fecundity of Amblyseius aerialis fed two-spotted spider mite

The mites of the Phytoseiidae family stand out for the biological control of pest mites. The species Amblyseius aerialis (Muma, 1955) is a generalist mite, which can contribute to the natural regulation of pest mites. The objective of this study was to evaluate the potential for predation and fecundity of A. aerialis on the different phases of Tetranychus urticae (Koch, 1836) (Acari: Tetranychidae). A female of A. aerialis was confined on dish (3.0 cm in diameter) of jack bean leaves, Canavalia ensiformis (L.) DC. The discs were left in petri dish with water. Each T. urticae phase was offered individually to A. aerialis at densities: 2, 5, 10, 15, 20 and 30 mites / arena. The number of prey consumed and eggs laid by A. aerialis were evaluated every 24 hours for seven days, with removal of laid eggs by phytoseiid and dead prey and replacement of prey in the initial amount. The data were submitted to analysis of variance and the means were compared by Tukey test, applying the factorial (4x6). It was observed that with the increase of the density of T. urticae offered there was an increase in the predation of A. aerialis. When offered the nymph and adult the average number of eggs per day was higher, differing from egg and larva. Thus, A. aerialis can be a biological control agent of the T. urticae, reducing the population of the pest and maintaining its fecundity in all phases and densities offered.

Interspecific interactions involving Neoseiulus californicus (Acari: Phytoseiidae) and Agistemus brasiliensis (Acari: Stigmaeidae) as predators of Brevipalpus phoenicis (Acari: Tenuipalpidae).

Brevipalpus phoenicis (Geijskes) is associated with the transmission of Citrus leprosis which is considered the main viral disease for the Brazilian citrus production. Mites of the families Stigmaeidae and Phytoseiidae coexist in various agricultural crops, often promoting the biological control of pest mites. The aim of this work was to study the interactions of Neoseiulus californicus (McGregor) (Phytoseiidae) and Agistemus brasiliensis Matioli, Ueckermann & Oliveira (Stigmaeidae), in the presence or absence of B. phoenicis. Two experiments were carried out. In the first, a N. californicus female was placed in each leaf disc arena, with eggs of B. phoenicis and A. brasiliensis as food sources. In the second, an A. brasiliensis female was placed in each arena, with eggs of B. phoenicis and N. californicus as food sources. Adults of both predators were able to consume both types of eggs available as food sources, but they fed on considerably higher proportions of B. phoenicis than on eggs of the predator. Eggs of A. brasiliensis were not a suitable food source for N. californicus, which produced only 0.1 egg per female per day when only eggs of that species were present in the experimental unit. The results suggest that eggs of N. californicus were a suitable food source for A. brasiliensis, which oviposited 1.12 eggs per day, when only eggs of N. californicus were provided to the stigmaeid mite. The possible interactions among N. californicus, A. brasiliensis and B. phoenicis in citrus orchards are discussed.

The role of native vegetation on infection rates of Calacarus heveae (Acari: Eriophyidae) by Hirsutella thompsonii (Ascomycota: Ophiocordycipitaceae)

Hirsutella thompsonii (Fischer) (Ascomycota: Ophiocordycipitaceae), a fungal pathogen, often causes high mortality in populations of Calacarus heveae Feres (Acari: Eriophyidae), an important pest mite in rubber tree plantations (Hevea brasiliensis Muell. Arg., Euphorbiaceae). However, the ecological and climatic factors regulating this host-pathogen system are poorly known. We compared fungal infections in agroforestry and traditional rubber plantations to evaluate the role of native vegetation and climatic factors on infection rates of C. heveae by H. thompsonii. While the prevalence of H. thompsonii was higher in managed rubber tree plantations, the abundance of C. heveae was about three times higher in traditional plantations. Abundance of C. heveae, agroecosystem management type and microclimatic variables were responsible for driving the infection rates of H. thompsonii. Native vegetation was a source for H. thompsonii and also modified the crop's microclimate, which contributed to its maintenance in the crop fields. Therefore, appropriate management practices may enhance the effects of entomopathogens on conservative biological control of pest mites in agroforestry systems.

ANÁLISE FAUNÍSTICA DE ÁCAROS FITOSEÍDEO SEM PINHÃO-MANSO E PLANTAS ESPONTÂNEAS ASSOCIADAS

RESUMO: O pinhão-manso (Jatropha curcas L.) destaca-se como fornecedor de matéria-prima de boa qualidade para a produção de biodiesel. Ácaros-praga causam danos significativos a essa cultura. Os ácaros predadores da família Phytoseiidae são os mais conhecidos em todo mundo e mais utilizados no controle biológico de ácaros-praga. A análise faunística propicia conhecimentos da dinâmica das espécies encontradas em determinado local e período de tempo. Objetivou-se com este trabalho analisar a fauna dos ácaros da família Phytoseiidae determinando-se a dominância, a abundância e a frequência das espécies, além da diversidade e equitabilidade dessas espécies, na cultura do pinhão-manso e nas plantas espontâneas associadas. Foram realizadas coletas mensalmente totalizando 12 meses. Para a amostragem dos ácaros nas plantas espontâneas, primeiramente foram confeccionadas 15 parcelas de 9 m² (3m x 3m). Foram coletadas 10 folhas de cada espécies de planta,com exceção das monocotiledôneas que foram 20. Para a coleta no pinhão-manso foram selecionadas 30 plantas, sendo coletadas nove folhas de cada. Para análise utilizou-se o softwear ANAFAU. Os ácaros Amblyseius sp., Typhlodromalus aripo, Typhlodromalus clavicus, e Typhlodromips mangleae destacaram-se tanto no pinhão manso quanto nas plantas espontâneas. Os predadores T. aripo foi dominante nas plantas espontâneas e T. clavicus foi superdominante no pinhão-manso. PALAVRAS-CHAVE: diversidade de espécies, Jatropha curcas L., Phytoseiidae, predador.

Acarofauna em cultivo de pinhão-manso e plantas espontâneas associadas

O objetivo deste trabalho foi identificar ácaros na cultura de pinhão-manso e em espécies de plantas espontâneas associadas. Para isso, foram avaliadas a riqueza e a abundância de ácaros em plantas de pinhão-manso e em 14 espécies de plantas espontâneas associadas. As amostragens foram realizadas por meio de coletas mensais de folhas de plantas de pinhão-manso e de plantas espontâneas, nas entrelinhas do cultivo. Foram encontradas quatro espécies de ácaros predadores - Amblyseius tamatavensis, Paraphytoseius multidentatus, Typhlodromalus aripo e Typhlodromalus clavicus -, com potencial para uso no controle biológico de ácaros-praga na cultura do pinhão-manso, e duas importantes espécies de ácaros fitófagos - Brevipalpus phoenicis e Tarsonemus confusus - desconhecidas como praga da cultura. Entre as plantas espontâneas avaliadas, quatro espécies - Hyptis suaveolens, Peltaea riedelii, Urochloa mutica e Andropogon gayanus - abrigam grande riqueza e abundância de ácaros predadores, enquanto oito destacaram-se pela diversidade de ácaros fitófagos.

Olfactory response of Typhlodromus pyri (Acari: Phytoseiidae) to synthetic methyl salicylate in laboratory bioassays

The herbivore-induced plant volatile (HIPV) methyl salicylate (MeSA) is widely present in the chemical profile of several plant species and is known to attract natural enemies, including predatory mites. In this study, the response of Typhlodromus pyri, a key predator of pest mites in west coast vineyards, to synthetically produced MeSA was tested using a Y-tube olfactometer in laboratory bioassays. Six doses ranging from 0.002 to 200 μg of MeSA diluted in 0.1 ml hexane were tested. Significantly higher proportions of T. pyri preferred MeSA at doses 0.02, 0.2 and 20 μg. No differences in response to MeSA were detected at the highest (200 μg), intermediate (2 μg) and lowest (0.002 μg) doses. Mite response to MeSA was a function of dose when fitting polynomial and logistic regression models using dose and square of the log dose prediction factors. Results indicate that synthetic MeSA may be applied to attract predatory arthropod populations in vineyards to enhance biological control of pest mites.

Influence of leaf trichomes on predatory mite density and distribution in plant assemblages and implications for biological control

Non-glandular trichomes on leaves or stems are strongly positively correlated with the abundance of many predatory phytoseiid mite species. Some perennial fruit crops have few or no trichomes and overcoming this limitation of leaf habitat for natural enemy mites could improve biological control of pest mites in agricultural crops. This study evaluated whether juxtaposing plants with and without trichomes will promote more abundant natural enemies throughout an ensemble of plants. We first asked whether the pattern of increased phytoseiid retention with higher trichome densities on a single leaf “scales up” to larger plantings. For three patch sizes (1, 4 or 16 plants) of two grape varieties inoculated with phytoseiids, no strong effect of patch size on Typhlodromus pyri Scheuten abundance was observed in the trichome-rich Baco plantings or in the trichome-free Dechaunac plantings. No predator populations established in Dechaunac plantings of any size. Second, we asked whether the addition of a plant with leaf trichomes within a row (“array”) of plants lacking leaf trichomes can increase phytoseiid density throughout arrays. In both a greenhouse and a field experiment, predatory mites moved onto and established on a neighboring plant only if that plant had trichomes; phytoseiids rapidly dispersed from trichome-free plants even when the plant was the one inoculated with predators. The overall number of phytoseiids decreased over time in ensembles that included both trichome-rich and trichome-free plants in the greenhouse and the field experiments, clearly indicating that for biological control programs to be successful, all plants must express trichomes.

Natural Biological Control of Pest Mites in Brazilian Sun Coffee Agroecosystems

Coffee is one of the leading commodities in tropical America. Although plantations are usually established under a canopy of trees in most producing countries in the region, Brazilian coffee is mostly produced under full sun conditions. Such simple, single-crop agroecosystems with intensive agrochemical inputs often suffer with pests like mites. Predatory mites of the family Phytoseiidae are the main natural enemies associated with pest mites in the field. However, these beneficial arthropods struggle to survive in intensive agroecosystems such as coffee monocultures due to unfavorable microclimatic conditions, widespread pesticide use, and lack of alternative food (pollen, nectar). Conservation biological control uses a range of management strategies to sustain and enhance populations of indigenous natural enemies such as predatory mites. We discuss here conservation biological control as a strategy to improve biological control of pest mites by native predatory mites in Brazilian coffee monocultures as well as some related patents. Keywords: Broad mite, coffee red spider mite, coffee ringspot mite, pesticide selectivity, predatory mites

Natural Biological Control of Pest Mites in Brazilian Sun Coffee Agroecosystems

Coffee is one of the leading commodities in tropical America. Although plantations are usually established under a canopy of trees in most producing countries in the region, Brazilian coffee is mostly produced under full sun conditions. Such simple, single-crop agroecosystems with intensive agrochemical inputs often suffer with pests like mites. Predatory mites of the family Phytoseiidae are the main natural enemies associated with pest mites in the field. However, these beneficial arthropods struggle to survive in intensive agroecosystems such as coffee monocultures due to unfavorable microclimatic conditions, widespread pesticide use, and lack of alternative food (pollen, nectar). Conservation biological control uses a range of management strategies to sustain and enhance populations of indigenous natural enemies such as predatory mites. We discuss here conservation biological control as a strategy to improve biological control of pest mites by native predatory mites in Brazilian coffee monocultures as well as some related patents.

Phytoseiid dispersal at plant to regional levels: a review with emphasis on management of Neoseiulus fallacis in diverse agroecosystems.

Dispersal behaviors of phytoseiid and tetranychid mites are key factors in understanding predator-prey dynamics and biological control of pest mites at different spatial levels in agricultural and natural ecosystems. In this review, ambulatory and aerial dispersal of both mite groups are discussed at spatial levels of leaf, plant, crop and region. Emphasis is on dispersal of phytoseiids, and specifically, the specialist-predator, Neoseiulusfallacis (Garman), and two-spotted spider mite prey, Tetranychus urticae (Koch). Dispersal aspects that are discussed are ambulation on a leaf; plant or in a prey patch; aerial dispersal between plants; behavior and aerodynamics of aerial take-off; modeling vs. monitoring of dispersal distance; fates of dispersing mites that land on soil substrates; plants as take-off platforms and landing targets for dispersers; and regional dispersal patterns and integrated mite management.

Within- and Between-Plant Dispersal and Distributions of Neoseiulus californicus and N. fallacis (Acari: Phytoseiidae) in Simulated Bean and Apple Plant Systems

Intra- and interplant movement and dispersal of Neoseiulus californicus (McGregor) and Neoseiulus fallacis (Garman) were studied on both lima bean, Phaseolus lunatus L., and apple branch, Malus pumila Miller, plant systems that were seeded with excess (50–100 per leaf) numbers of the twospotted spider mite, Tetranychus urticae Koch. Individuals of either predator were selected randomly from colonies of well-fed, mixed-age adult females and moved to test plants. When tested separately in each plant system, N. californicus dispersed a greater distance from the point of release than N. fallacis at 1–8 d. A fan placed in front of bean plants containing T. urticae and near equal densities of both predaceous mites, provided continuous air (wind) to 3 isolated receiver units located 2.5, 5, and 7.5 m downwind. Receiver units consisted of continuous bean foliage with excess (50–100 per leaf) T. urticae , but no predators. Wind speeds at the source and each receiver unit averaged 2.2, 0.9, 0.4, and 0.03 m/s. As predators eliminated prey, N. fallacis dispersed earlier at higher prey densities and further downwind than N. californicus , but cumulative densities of each predator in all receiver units were alike after 20 d. Results of both within- and between-plant dispersal studies supported the hypothesis that N. californicus has dispersal traits more like those of a generalist predator of spider mites than does N. fallacis . Spatial patterns of dispersal and biological control of pest mites are discussed in relation to predation types within the Phytoseiidae.

Populations of predatory and pest mites in first‐level and second‐level commercial apple orchard blocks in Massachusetts

Abstract: Populations of predatory and phytophagous mites were sampled weekly throughout the growing season in first‐ and second‐level integrated pest management (IPM) blocks in 12 commercial apple orchards in Massachusetts in 1993. In first‐level blocks, insecticides were used throughout the growing season. In second‐level blocks, no insecticides were sprayed after early June. Among the 12 orchards, 92% contained Amblyseius fallacis, 8% contained Typhlodromus pyri and 50% contained Zetzellia mali as predaceous species, while 100% contained Panonychus ulmi and 58% contained Tetranychus urticae as pest species. When averaged over the entire season, populations of predaceous A. fallacis and Z. mali and populations of pest P. ulmi were numerically, but not statistically, greater in second‐level blocks than in first‐level blocks. The opposite was true for T. urticae. Initial time of appearance of each species was about the same in both types of blocks. Panonychus ulmi peaked in mid‐July, much earlier than A. fallacis, the most frequently observed predaceous mite. Populations of the latter peaked in September at relatively low densities, too late in the growing season for this species to provide, by itself, timely biological control of pest mites. Winter mortality from cold temperatures and spring/summer mortality from the use of fungicides are suspected to be the principal agents responsible for the slow build‐up of A. fallacis. Zetzellia mali was present in early spring and increased slowly until reaching peak levels in autumn. Absence of pre‐bloom oil and other acaricide sprays in a small portion of each second‐level block did not facilitate build‐up of predaceous mites, but did result in rapid build‐up of P. ulmi.