Tetranychus neocaledonicus, the commonly called vegetable spider mite is a highly polyphagous pest, infesting over 500 species of economic plants. The species has been categorized as a major pest, inducing considerable feeding damage on vegetables, fruit crops, medicinal plants, ornamentals, plantation crops etc. The present study was concentrated to assess the predatory potential of a phytoseiid predator, Neoseiulus longispinosus on the different life stages (egg, larva, nymphs and adults) of T. neocaledonicus under laboratory conditions. Separate experimental set ups were prepared with leaf arena of mulberry plants and known numbers of different life stages of the pest mite were maintained on individual leaf arena. For evaluating the predatory potential, adult females of N. longispinosus were introduced on to the individual leaf discs in the arenas and observations were made under a stereomicroscope to record the response of the predator to the individual life stage of the pest mite. The number of prey stages consumed by the predator on individual leaf arena was recorded for a time interval of 24 hrs and the rate of consumption on individual prey instar was calculated. Except at the time of oviposition, the adult predator was found to make active prey searching movement randomly, in and around the prey patches. By sensing the prey through successive contacts with the first pair of legs and pedipalps, the predator initiated feeding actively, and sucked out the entire fluid content with its mouth parts. The adult predator showed a specific preference to feed on the egg stage of the prey mite while the predator nymph exhibited preference to the nymphal stages of the prey. A decreasing sequence in the order egg > larva > nymphs> adult was recorded in the feeding preference of the adult predator towards life stages of the prey mite and the per cent consumption on egg, larva, nymphs and adult female stages was 48.4, 29.9, 26.6 and 9.3 %, respectively. However, the feeding preference of the nymphal stage of the predator showed a slight deviation in the order nymph > larva > adult > egg and the mean rates of consumption were 31.3, 22, 11.2 and 10.3 %, respectively. Data gathered on consumption rates of the predator upon statistical analysis revealed a significant variation towards different stages of T. neocaledonicus, thereby establishing a specific preference to prey eggs by the predator.

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Tetranychus macfarlanei Baker and Pritchard is considered as a major spider mite pest infesting various agricultural crops across the globe. It is a highly polyphagous species, inducing heavy yield loss annually, thereby affecting the agriculture sector drastically. As an eco-friendly pest management strategy, biological control using phytoseiid predators is gaining significant attention all over the world during the past few decades. Evaluation of predatory potential and prey stage preference provides valuable information on the efficacy of the predatory species in controlling the pest population. Considering this, a comparative evaluation of the feeding preference of a phytoseiid predator, Neoseiulus longispinosus (Evans), was made on different life stages of T. macfarlanei under laboratory conditions of 30±20C and 70±5% RH. The experimental arena used for the feeding experiments consisted of mulberry leaf discs (2 cm2) uniformly arranged over 2% semi-solidified agarose medium placed inside a glass Petri dish. The results revealed that the feeding preference of the adult predator towards the prey stages after 24 hours of experiment followed a decreasing sequence of egg (68%)> nymph (13.3%)> larva (6.6%). The predator nymph also followed a similar order of preference with respective consumption rates of 22%, 6.6% and 6.6% on the egg, larva and nymph of the prey mite, indicating that both the nymphs and the adult females of the predator displayed a significant preference to feed on the eggs of T. macfarlanei. Both predatory life stages showed no preference to the adult females of T. macfarlanei. Statistical analysis using ANOVA revealed a significant variation (p < 0.05) in the feeding preference of the predatory life stages towards the varied prey stages. Thus, the results of the study clearly showed the bio-control potential of N. longispinosus against T. macfarlanei.

Spider mites are considered as a potential threat to varying agricultural crops across the globe. Among the agriculturally important spider mite species, Tetranychus urticae Koch and Tetranychus macfarlanei Baker and Pritchard severely affect crop production and incur heavy yield loss in agriculture sector. As an ecofriendly pest management strategy, biocontrol using phytoseiid predatory mites are gaining significant attention over the past few decades. Evaluation of predatory potential and prey stage preference could provide invaluable information on the predatory efficiency of any predators. Feeding experiments were conducted using the phytoseiid predatory mite, Neoseiulus longispinosus (Evans) on mulberry leaf discs under the laboratory conditions of 30±2ºC, 70±5% Relative Humidity (RH) and a photoperiod of 11 L: 14 D h. After 24 hr of feeding experiment, the nymph and adult female predator exhibited a significant preference in feeding towards the eggs of T. urticae and T. macfarlanei. The larval stage of the predator was found to be non-feeding, thus excluded from the feeding experiment. The order of feeding preference of adult female predator towards different life stages of both the spider mite species were identified as egg>nymph>larva>adult. On the contrary, the predatory nymphal stage exhibited different trend in feeding preference towards the life stages of T. urticae and could be recorded as egg>larva>nymph>adult. For T. macfarlanei, the same could be found as egg>larva=nymph>adult. Surprisingly, irrespective of the life stage differences, N. longispinosus hardly consumed any of the T. macfarlanei adults.