Persian Journal of Acarology

Abstract The yellow date palm mite, Oligonychus afrasiaticus (McGregor), commonly known as “Boufaroua” in North Africa, is one of the most destructive pests affecting date palm production in the Ziban region of southeastern Algeria. Despite its economic importance, limited information is available on the ecological role of spontaneous weed flora in maintaining mite populations and facilitating seasonal infestations of date palms. Therefore, the present study aimed to identify weed species that may serve as alternative hosts of O. afrasiaticus, to determine their contribution to the seasonal persistence of the mite, and to evaluate how seasonal plant phenology and spatial variation among palm groves influence infestation dynamics. A six-month field survey was conducted from February to July 2021 in seven representative palm groves of the Ziban oases. The occurrence of O. afrasiaticus was monitored on date palms and associated weed species in relation to seasonal dynamics and spatial variation among sites. The mite was detected in all surveyed groves, with infestation intensity varying according to microclimatic conditions and grove management practices. Among date palm cultivars, Deglet Nour exhibited the highest susceptibility. A total of 76 weed species were recorded, of which five species (Cynodon dactylon, Daucus carota, Aster squamatus, Kochia scoparia, and Salsola tetragona) were confirmed as alternative hosts capable of sustaining mite populations. Infestation patterns showed a clear seasonal progression, with early establishment on herbaceous weeds during spring followed by a shift toward date palms under hot and dry summer conditions. These findings demonstrate that weed communities play a significant ecological role in the persistence and spread of O. afrasiaticus within oasis agroecosystems and highlight the importance of integrating targeted weed management into integrated pest management strategies for sustainable date palm protection.

Abstract The coffee red mite, Oligonychus coffeae (Nietner), is a pest of major agricultural importance in tropical regions. This study evaluated the in vitro effect of two host plants, coffee (Coffea arabica) and Andean alder (Alnus acuminata), on the biological cycle and population parameters of O. coffeae under controlled conditions (25 ± 1 °C, 70 ± 5 % RH, and a 16:8 h photoperiod). In addition, the acaricidal activity of ethanolic extracts of coffee and alder at concentrations of 5, 10, and 20% (w/v) was assessed using a leaf-dip bioassay, with mortality recorded at 24, 48, and 72 h and compared with a synthetic acaricide (propargite). The development of O. coffeae was significantly faster on coffee leaves (13.8 days) than on alder (16.2 days); however, fecundity and adult longevity were higher on alder, reaching 59.9 eggs per female. Population parameters were significantly higher on alder (rₘ = 0.254 day−¹; R0 = 52.4 female eggs/female), indicating a greater population growth potential on this host. The ethanolic extracts exhibited dose- and time-dependent acaricidal activity; at 72 h, the 20% concentration caused mortalities of 91.2% on coffee and 89.3% on alder, comparable to propargite. These results indicate that both host plants favor the development of O. coffeae and that their ethanolic extracts represent promising alternatives for the integrated management of this pest.

Abstract Amblyseius swirskii Athias-Henriot (Acari: Phytoseiidae) is an important generalist predator used to control several important crops' pests such as spider mites, whiteflies, and thrips. In this study, the lethal concentrations of Mentha piperita L. (Lamiaceae) and Laurus nobilis L. (Lauraceae) essential oils (EOs) were calculated on the adult stage of the Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). The side effects of EOs were investigated on the functional response of A. swirskii on F. occidentalis 1^st instar larvae. The females of A. swirskii were exposed to sub-lethal concentrations (LC₃₀ and LC₅₀) of EOs for 12 h with the fumigant exposure method. In the control, the treatment was performed by using Triton X-100 (0.02). Treated predatory mites were selected randomly, and transferred to the experimental arenas containing 2, 4, 8, 16, 32, and 64 thrips. The predators were kept in the experimental arenas for 24 h at 25 ± 1 °C, 60 ± 10% RH, and a photoperiod of 16: 8 h (L: D). Results indicated that A. swirskii exhibited a type II functional response, regardless of EOs applications. The shortest (1.62 ± 0.046 h) and the longest (1.91 ± 0.049 h) handling times, were recorded in the control and the LC₅₀ treatment of M. piperita EO, respectively. There was not a significant difference between attack rate coefficients (α) under sub-lethal concentrations. Based on the results, the two EOs have the potential to be used in F. occidentalis management, but their side effects on A. swirskii should be considered in IPM programs.

Abstract The two-spotted spider mite, Tetranychus urticae Koch (Acari: Tetranychidae) is a serious pest that infests different agricultural crops in Bangladesh. The application of different types of pesticides (botanical and chemical) with various modes of action and bio-pesticides was used for the first time to develop sustainable pest control strategies against spider mites. In this study, the effects of six chemical insecticides viz. abamectin, bifenthrin, bifenazate, etoxazole, hexythiazox, and spinosad, and entomopathogenic fungus Beauveria bassiana and botanical neem oil were evaluated against adult and egg stages of T. urticae under laboratory conditions. Treated mites were kept in controlled conditions at 25 ± 1 ℃, 60–70% RH and a photoperiod of 16:8 h (L: D). The LC₅₀ values of all chemicals [for adults, abamectin (0.51 ml/L), bifenthrin (3.26 ml/L), bifenazate (3.82 ml/L), hexythiazox (3.27 ml/L) and spinosad (3.83 ml/L); for eggs, abamectin (0.56 ml/L), bifenthrin (3.48 ml/L), bifenazate (26.81 ml/L), hexythiazox (4.18 ml/L) and spinosad (18.28 ml/L)] suggest that they were effective against eggs and adult females of the T. urticae. Etoxazole (LC₅₀ = 3.99 ml/L) is recommended against egg stage. The neem oil was found to be moderately effective (for adult, LC₅₀ = 1.26%; for egg, LC₅₀ = 1.77%) against eggs and adult females of T. urticae. The B. bassiana was also found to be effective against eggs and adult females of T. urticae. Finally, it could be concluded that all chemicals used in this study are effective for the management of two spotted spider mite but the entomopathogenic fungus B. bassiana and botanical neem oil were promising alternatives for successful management of T. urticae in IPM programs.