Search

Diet is an important component of mass-production system of bio-control agents. Thus, using a non-prey diet (such as plant pollen) instead of natural prey could be more cost-effective in mass-production of phytoseiid predatory mites. Therefore, the present study aimed to examine the multigenerational effect of maize, Zea mays L. (Poaceae), pollen diet on life table parameters of Amblyseius swirskii Athias-Henriot and Cydnoseius negevi (Swirski & Amitai) (Acari: Phytoseiidae) reared for one, five and 11 consecutive generations. The predatory mites A. swirskii and C. negevi successfully completed their development on maize pollen for up to 11 generations. In G1, oviposition days, adult longevity, and fecundity showed significantly higher values in the case of C. negevi as compared to A. swirskii. Despite statistically similar oviposition days in the G11, A. swirskii females (44.43 eggs/♀) deposited significantly more eggs than those of C. negevi (40.60 eggs/♀). There were no significant differences in finite rate of increase (λ), intrinsic rate of increase (r), net (R0) and gross (GRR) reproductive rates between the two predatory mites in G1 and G5 (P ≥ 0.05). In G11, individuals of C. negevi had significantly higher values of r (0.181 day-1) and λ (1.198 day-1) compared to those of A. swirskii (r = 0.159 day-1, λ = 1.173 day-1). However, there were no significant differences in R0 and GRR values between A. swirskii (R0 =34.18 offspring, GRR = 39.75 offspring) and C. negevi (R0 = 31.23 offspring, GRR = 35.44 offspring) in G11. In conclusion, maize pollen has a great potential as a suitable and cost-effective diet for developing the mass-production system of A. swirskii and C. negevi on non-prey diets, where the performance of these predators remained to some extent constant across generations. [ABSTRACT FROM AUTHOR]

Phytoseiidae mites' survival and reproduction depend on optimal environmental factors. A total of five different agroecological zones (AEZs) were surveyed twice each year from 2017 to 2019 in Kenya. In Eastern Kenya sample farms were small scale citrus orchards in the counties of Machakos [Low Midlands-Four (LM4)] and Makueni [Upper Midlands-Three (LM3)]. In the Coastal Lowlands-Four (CL4) similar small-scale citrus plots were sampled in Kwale, while in the highland Rift Valley region sample sites were ADC-Suam orchards of Kitale of the Lower Highlands-Two (LH2), where the large-scale farms were under citrus crop culture. The fifth site sampled was Baringo area of the Low Midlands-Five (LM5) where small plot citrus crop dominated the sample sites. Out of 68 fields of repeat surveys, 40% of citrus plots yielded varied diversity of phytoseiid mites. The major pest from the sites was citrus brown mite, Eutetranychus africanus. In this study, population fluctuation of phytoseiid mites was observed under different climatic conditions of temperature, relative humidity, dew-point and citrus plant age (in years). On the major pest E. africanus, three factors were evaluated for correlation and significance to infestation levels on the citrus crop. Of the three evaluated factors of temperature, citrus tree age and phytoseiid density in the orchards, temperature parameter did not significantly influence the pest mite (E. africanus) infestation levels for all combined AEZs factors. In the present case studies of specific AEZs, older trees led to higher pest mite density while low phytoseiid numbers correlated inversely to higher E. africanus infestation levels on the citrus trees. The information here could be used proactively to plan for management of E. africanus as the major pest in citrus orchards in specific agro-ecological zones. [ABSTRACT FROM AUTHOR]

The suitability of eight pollen diets (wild almond, date palm, oak, pomegranate, pistachio, peach, damask rose, and walnut) and also Tetranychus urticae Koch as natural diet on life table of the Amblyseius swirskii (Phytoseiidae) was determined at 25 ± 1 °C, 60 ± 5% relative humidity and photoperiod of 16:8 h (L: D). Results showed that damask rose pollen was not accepted as food and did not support the development of A. swirskii beyond the protonymphal and deutonymphal stage. The highest and lowest values of the intrinsic rate of increase (r) and finite rate of increase (λ) belonged to the pistachio (0.192 and 1.212 day-1) and peach (0.022 and 1.023 day-1) pollen, respectively. The net reproductive rate (R0) values varied from 1.4 offspring for the peach pollen to 29.54 offspring for the pistachio. Furthermore, the highest and lowest fecundity rate was recorded on the pistachio (36.65 eggs/female) and peach (3.23 eggs/female) pollen, respectively. Measured life table parameters of A. swirskii reared on different diets revealed pistachio, and after that, date palm and pomegranate pollen grains to be the most suitable diets. These findings may introduce more suitable pollen diets for the rearing of this predatory mite. [ABSTRACT FROM AUTHOR]

Two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) and silverleaf whitefly, Bemisia tabaci (Gennadius) (Hem.: Aleyrodidae) are among the most destructive pests under greenhouse conditions which is primirarily countered using chemical pesticides. Due to insecticidal and acaricidal effectiveness of Spiromesifen (Oberon®), agricultural producers extensively used this chemical to control both whitefly and spider mite populations. In the present study, effects of recommended concentration of Spiromesifen on some biological and behavioral attributes of predatory mite Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) feeding on different ratios of two-spotted spider mite and silverleaf whitefly were investigated. Different treatments were defined as 1 (150 immature stages of mite + 0 immature stages of whitefly), 2 (120 mite + 30 whitefly), 3 (90 mite + 60 whitefly), 4 (75 mite + 75 whitefly), 5 (60 mite + 90 whitefly), 6 (30 mite + 120 whitefly) and 7 (0 mite + 150 whitefly). According to the results, mortality percentage of adult individuals was not significantly affected by different ratios of prey. With increasing ratio of preys tested in experimental arena, feeding activity of predatory mite on both preys was increased. However, in the case of T. urtice, linear relation observed between the initial number of mite offered and number of mite eaten was more significant. Reproductive responses of female predators to different ratios of mixed preys had no specified trend. Furthermore, switching behavior was not detected in female predators. Our results have considerable role for increasing biological efficacy of A. swirskii in integrated management programs of different pests. [ABSTRACT FROM AUTHOR]