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Southern red mite, Oligonychus ilicis McGregor (Acari: Tetranychidae), is an important polyphagous spider mite pest that causes economic damage to many ornamentals, coffee, and fruit crops. Blueberry growers in the Southeastern United States, including Florida and Georgia, have experienced severe losses due to outbreaks of O. ilicis. Predatory mites are an important management tool used for controlling spider mites; however, predators have not been studied and successfully evaluated in blueberry systems. Amblyseius swirskiiAthiasHenriot, Phytoseiulus persimilis Athias-Henriot, and Neoseiulus californicus (McGregor) (Acari: Phytoseiidae) are among the most economically important arthropod agents used in augmentative biological control worldwide.To evaluate the potential of these 3 commercially available predatory mites for use in blueberry plantings, we conducted experiments under controlled laboratory conditions and in the greenhouse. In preliminary laboratory experiments, P. persimilis and N. californicus significantly reduced the number of O. ilicis motile stages below those found in the untreated control, indicating the potential for these 2 predatory mite species to suppress O. ilicis populations. Amblyseius swirskii did not perform well controlling O. ilicis motiles in the laboratory. Under greenhouse conditions, N. californicus and P. persimilis significantly reduced the number of eggs after 7 days of release and the number of motile stages after 14 days of release.This is the first report of using phytoseiid mites to suppress O. ilicis in blueberry systems in the United States. Further studies on predator behavior, feeding preferences, and acaricide compatibility with predators are required to investigate the possibility of using P. persimilis, and N. californicus as biological control agents of O. ilicis in blueberry systems.

Erythritol, an artificial sweetener, has shown promise as an organic, human-safe insecticide. Recently, erythritol applications were shown to be successful at controlling pear psylla (Cacopsylla pyricola (Förster)) (Hempitera: Psyllidae), the most important pest of pear in the Pacific Northwest, USA.Twospotted spider mite (Tetranychus urticae Koch) (Trombidiformes:Tetranychidae) and pear rust mite (Epitrimerus pyri (Nalepa)) (Trombidiformes: Eriophyidae) can also be highly damaging pear pests.Their common natural enemy, Galendromus occidentalis (Nesbitt) (Mesostigmata: Phytoseiidae), can provide biological control if selective pesticides are used for managing other pests.Through a series of bioassays, we sought to determine whether erythritol could also be used for controlling either species of pest mite. We also examined whether erythritol had acute or sublethal impacts on G. occidentalis, through a variety of exposure methods. Effects examined included mortality, fecundity, prey consumption, and locomotion. We determined that a high concentration of erythritol (30%) had efficacy against both pest mite species and caused arresting behavior in twospotted spider mite. Erythritol caused little acute mortality in G. occidentalis, but did reduce fecundity and prey consumption through some exposure methods. Through motion-capture software, we determined that this is primarily due to reduced movement, likely caused by difficulty walking on residues and excessive grooming behavior. Because the predatory mite non-target effects were less acute than those for the two pest mites, we concluded that erythritol could likely be integrated into pear IPM with little or no disruption of mite biological control.

The phytoseiid predatory mite Neoseiulus californicus (McGregor) is one of the most efficient biocontrol agents in integrated pest management (IPM) programs of greenhouse pests, with different feeding habits on pollen, thrips, eriophyiids, and spider mites. This study appraised the effect of the age and gender on functional response and age on numerical response of N. californicus fed on larvae and protonymph of Tetranychus urticae Koch under laboratory conditions at 25 ± 1 ℃, 70 ± 5% RH and a photoperiod of 16L: 8D h. In the functional response test, the 2, 4, 8, 16, 32, 64, and 128 densities of prey were offered to 3, 5, 7, 10, 15, 20, 25, 30, 35 and 40-day-old ages of female and 7, 10, 15, 20, 25 and 30-day-old ages of male individuals of N. californicus . The logistic regression was used to recognize the type of functional response. Type II functional response was recognized for all ages of the male and female individuals of N. californicus . The highest predation rate, and searching efficiency ( a ) was observed in the middle ages of the predator. A significant increase in oviposition was shown with increasing T. urticae density and increasing ages of the predator. Furthermore, in the middle age with low prey density, the efficiency of conversion of ingested food (ECI) was the highest. The results of this study showed that the different ages of N. californicus are influencing factors on its predation capacity and oviposition rate.

The predatory mite, Neoseiulus bicaudus (Wainstein), is a potential biological control agent against spider mites and thrips. The objective of this experiment was to compare the effects of three diets on the life table of N. bicaudus. The three diets were 1) Tetranychus turkestani (Ugarov & Nikolskii) (Acari: Tetranychidae), the natural prey of N. bicaudus; 2) Tyrophagus putrescentiae (Schrank) (Acari: Acaridae), an alternative prey; and 3) artificial diet primarily consisting of decapsulated shrimp cysts, egg yolk, and honey. The computer simulation was used to project the population growth of N. bicaudus fed on different diets. The preadult developmental time (3.83 d) of N. bicaudus was shortest, and the intrinsic rate of increase (r = 0.2782 d-1) and the net reproductive rate (R0 = 18.98 offspring) were highest when reared on the alternative prey Ty. putrescentiae. The total development time (7.37 d) was longest, and the population parameters were the lowest (r = -0.0081 d-1, R0 = 0.85 offspring) when N. bicaudus was reared on artificial diet. The population projection showed that the population of N. bicaudus reared on Ty. putrescentiae could increase fast. Our results showed that the Ty. putrescentiae was the most suitable prey for mass rearing of N. bicaudus. The artificial diet could not support the N. bicaudus population and needs to be improved.

The two-spotted spider mite, Tetranychus urticae, is a significant pest of cucumber crops, particularly under polyhouse conditions. Effective management strategies are essential for maintaining crop yield and health. Therefore, the efficacy of anthocorid bug, Blaptostethus pallescens and predatory mite, Neoseiulus longispinosus were evaluated along with Spiromesifen 45 SC against the two-spotted spider mite on cucumber. It involved comparing the impact of Spiromesifen 45 SC, N. longispinosus at two predator-to-prey ratios (1:20 and 1:30) and B. pallescens at two different densities (10 and 20 nymphs per meter row) on T. urticae. Assessments were made on mite counts and fruit yields over two growing seasons (2020 and 2021). The study revealed that the minimum count of spider mite was recorded with Spiromesifen 45 SC which differed statistically with other treatments. The next best treatment was N. longispinosus (1:20 predator: prey), followed by N. longispinosus (1:30 predator: prey), B. pallescens (20 nymphs/m row) and B. pallescens (10 nymphs/m row) Besides the use of insecticide, N. longispinosus (1:20 predator: prey) can be used as one of the components of Integrated Pest Management Programme for the management of red spider mite, T. urticae infesting cucumber under polyhouse conditions. The correlation studies on population of mite, T. urticae with weather parameters concluded a significant positive correlation with maximum, minimum and average temperature while, significant negative correlation with morning, evening and average relative humidity. The study concludes that both B. pallescens and N. longispinosus has great potential in managing T. urticae and it can be used to control mite population.

The twospotted spider mite, Tetranychus urticae (Koch) (Acari:Tetranychidae), is a key pest of strawberries and many other crops worldwide. Cover cropping, selecting tolerant or resistant cultivars, and biological control are important strategies of an organic management plan. In this study, we examined the effect of summer cover crops and strawberry cultivars on populations of T. urticae and a commercially available predatory mite, Neoseiulus californicus McGregor (Acari: Phytoseiidae), commonly used for T. urticae management in Florida. In the 2013–2014 season, four cover crops and eight strawberry cultivars were screened at the research station and on a commercial organic strawberry farm. The following season, the most promising cover crops (sunn hemp and hairy indigo) and cultivars, ‘Sensation', ‘Strawberry Festival', and ‘Winterstar' were tested at the research station and on two small organic farms. In the 2016–2017, 2017–2018, and 2018–2019 seasons, a 4-way mix of cover crops was compared to sunn hemp and hairy indigo. In 2016–2017, ‘Florida Radiance' was added to the three previously selected cultivars. ‘Florida Beauty' replaced ‘Strawberry Festival’ in 2017–2018 and 2018–2019, and ‘Florida Brilliance’ replaced ‘Winterstar’ in 2018–2019. The effects of summer cover crops on both T. urticae and N. californicus were minimal. ‘Florida Brilliance’, ‘Florida Radiance’, ‘Sensation’, ‘Strawberry Festival’, and ‘Winterstar’ had lower T. urticae populations and higher yields in most seasons at most locations. The establishment and abundance of N. californicus was similar on these cultivars and was generally higher where T. urticae populations were higher. Implications for organic strawberry production in Florida are discussed.

Predatory mites are important biological control agents used against phytophagous mites and small insects. They face various environmental pressures, especially fluctuating climate factors. Neoseiulus californicus, a commercially available phytoseiid mite, is adapted to a wide range of temperature conditions. We investigated the regulatory mechanisms governing the plastic response of N. californicus for coping with environmental temperature variations. The mitogen-activated protein kinase (MAPK) signaling pathway is a highly conserved pathway of cell signal transduction that responds to environmental stress. We isolated two MAPKK genes (NcMAPKK4 and NcMAPKK6) from N. californicus and studied their functions. Developmental stage–specific expression level analysis showed that in adults, particularly females, NcMAPKK4 and NcMAPKK6 levels were higher than in other developmental stages. The expression level analysis at extremely high and low temperature conditions demonstrated that NcMAPKK4 could be induced significantly by adverse thermal stresses, whereas NcMAPKK6 distinctly responded to heat shock, indicating their different roles in thermal stress responses. After silencing of NcMAPKK4, both heat and cold resistance decreased significantly, whereas NcMAPKK6 knockdown had a greater influence on heat resistance. Knockdown of NcMAPKKs also reduced the activities of antioxidant enzymes, suggesting the regulation of NcMAPKKs was closely related to the antioxidant process in oxidative stress caused by external stimuli. These results indicate an important role of NcMAPKKs in the response to thermal stress and provide insight into the MAPK cascade pathway in the environmental adaptation mechanisms of phytoseiid mites.

Amblyseius swirskii Athias-Henriot (Parasitiformes: Phytoseiidae) is one of the most common predatory mite species naturally occurring in several crops including citrus and vegetables in certain areas of the Mediterranean basin. Despite its abundance, and importance in sustainable pest management programs, there has been a notable gap regarding the compatibility of reduced-risk pesticides with this predatory mite. Hence, it is crucial to clarify the toxic effects of pesticides to assess the potential risk they pose to this predator and understand their environmental impact. Therefore, we evaluated the toxic effects of the six “reduced risk” pesticides, fosetyl-Al, prothioconazole + spiroxamine, proquinazid, tebuconazole, spinetoram and spinosad on different developmental stages of A. swirskii. To construct the possible “worst-case scenario”, the test units were sprayed at the maximum recommended concentrations of the pesticides. The results indicate that spinetoram, spinosad and proquinazid are highly toxic, which respectively caused 81.20%, 64.98% and 43.34% mortality on eggs, 100.00%, 100.00% and 96.66% on larvae, and 100.00%, 100.00% and 90.00% on adult females. While fosetyl-Al, prothioconazole + spiroxamine, and tebuconazole are harmless to eggs, they are moderately toxic to larvae and adult females with mortality rates respectively reaching 23.64%, 32.00% and 26.66% for larvae and 21.66%, 29.16% and 19.16% for adult females. Although all pesticides significantly reduced the egg production, higher effects were observed with application of spinetoram, spinosad, prothioconazole + spiroxamine and proquinazid. Therefore, the moderately toxic pesticides fosetyl-Al, prothioconazole + spiroxamine and tebuconazole may be compatible with A. swirskii in IPM programs. However, further investigations are essential to determine whether the highly toxic effects of other pesticides are consistent in semi-field and/or field conditions.

The predatory mite Neoseiulus barkeri (Hughes) is a good biological control agent for many small sucking pests. We aimed to determine whether rearing long term on alternative prey versus target prey species affected the performance of N. barkeri. Therefore, we investigated the prey preference, life tables, and population parameters of N. barkeri between alternative prey Tyrophagus putrescentiae (Schrank) and three species of spider mites, Tetranychus urticae Koch, Panonychus citri (McGregor), and Eotetranychus kankitus Ehara. We found that N. barkeri preferred the tetranychid mites to the alternative prey. Between the tetranychid mites, the predator consumed more P. citri and E. kankitus than T. urticae. When reared on T. urticae, the total developmental time and longevity of N. barkeri were the longest, whereas the intrinsic rate of increase was the lowest, indicating that the biotic fitness of predatory mite preyed on target of T. urticae was higher than on alternative prey of T. putrescentiae. However, total developmental time, longevity, and fecundity did not differ between N. barkeri reared on T. putrescentiae and P. citri, although these parameters were higher than those for mites reared on E. kankitus, indicating that the predatory mite reared on T. putrescentiae may not be affected to control P. citri, and that coexistence of P. citri and E. kankitus may enhance the control efficiency of N. barkeri. Altogether, our results demonstrated that long-term feeding on the alternative prey T. putrescentiae did not affect the performance of the predatory mite N. barkeri on various target spider mites.

Many predatory mites use insects for dispersal; however, their possible negative effects on insect hosts during transportation and on insect offspring while preying in the hosts’ habitats are still poorly understood. A recent study has revealed that the predatory mite Blattisocius mali can not only spread by means of drosophilid fruit flies but also feed on their bodies during dispersal. The aim of this study was to examine the capability of B. mali to prey upon the eggs of their fruit fly hosts and determine the effect of the egg’s age on the voracity of this predator. Drosophila melanogaster oviposited on agar media for 1 h and D. hydei for 8 or 16 h. During 10-h experiments with fifteen fly eggs per cage, a single female predator totally consumed on average 3.62 ± 0.673 “1-h” D. melanogaster eggs and 3.00 ± 0.612 “8-h” eggs of D. hydei, while it partially consumed 2.75 ± 0.586 and 3.00 ± 0.612 eggs of each fly species. In the experiments involving D. hydei, the predator totally destroyed a similar number of “8-h” and “16-h” eggs, but it partially consumed significantly more younger eggs than older eggs. Ethological observations showed that mites returned to some partially fed eggs, usually from the side where the first puncture was made, and only then did they consume them whole.