Kepadatan populasi dan waktu efektif pelepasan tungau predator Neoseiulus longispinosus Evans untuk pengendalian Tetranychus kanzawai Kishida

Kanzawa spider mite, Tetranychus kanzawai Kishida (Tetranychidae) is one of the most important pest mite in Indonesia. This mite is known as the pest of many crops, including cassava. Neoseiulus longispinosus Evans (Phytoseiidae) is a predatory mite commonly found on plant infested by kanzawa spider mite. This predatory mite has high potential to be developed as biological control agent of T. kanzawai. The aim of this research is to elucidate the effective density and release time of N. longispinosus to control T. kanzawai on cassava. The research was conducted in the greenhouse, using cassava of Mentega cultivar. T. kanzawai were introduced into the cassava plants two weeks after planting, with density 5 female adults/plants. N. longispinosus were introduced 1, 2, and 3 weeks after T. kanzawai introduction with predator:prey ratio of 0:5, 1:5, 2:5, dan 3:5, respectively. Population of T. kanzawai and N. longispinosus, and also plant damage were observed at 6 weeks after planting. N. longispinosus could suppress T. kanzawai population and the highest suppression occurred at the interaction between 3:5 ratio and the release time at one week after T. kanzawai infestation. There was no significant effect of N. longispinosus release at various release ratio and time on attack intensity of T. kanzawai.

Five new species and re-description of eight species belonging to the family Phytoseiidae (Acari: Mesostigmata) from West Bengal, India

This paper reports on 13 species of Phytoseiidae (Acari: Mesostigmata) from West Bengal, India. Eight species, namely Euseius alstoniae (Gupta, 1975), Paraphytoseius orientalis (Narayanan, Kaur & Ghai, 1960), Amblyseiulella heveae (Oudemans, 1930), Gynaeseius ricini (Ghai & Menon, 1969), Neoseiulus longispinosus (Evans, 1952), Neoseiulus imbricatus (Corpuz & Rimando, 1966), Neoseiulus barkeri Hughes, 1948 and Phytoseius kapuri Gupta, 1969 are re-described, and five species, Typhlodromips jhilimiliensis sp. nov, Typhlodromips neosyzygii sp. nov, Proprioseiopsis amari sp. nov, Typhlodromus (Anthoseius) bolpurensis sp. nov, and Phytoseius mauritiana sp. nov. are described as new. Neoseiulus barkeri Hughes, 1948 is reported from India for the first time.

Morphological ontogeny and molecular analyses of geographic strains of two closely related Neoseiulus species (Acari: Phytoseiidae)

The predatory mites, Neoseiulus longispinosus (Evans) and N. womersleyi (Schicha) (Phytoseiidae) are two morphologically close species. Although they can be mainly separated by the length of the dorsal seta S5, misidentifications may occur. The present study investigated various strains of the two closely related species collected from Japan, Taiwan and/or Thailand using a combination of morphological and molecular data. We described and illustrated the adults and immature stages. We also sequenced the 28S region of nuclear ribosomal DNA to determine whether these strains represent different species. The two species could be clearly separated based on the length of seta S5 and the ratio of setae Z5/S5. In a 28S tree, the examined strains also formed separate clades with 100% bootstrap values. We conclude that a combination of different methods is often necessary to precisely distinguish these closely related taxa.

Phytoseiidae of Vietnam (Acari: Mesostigmata) with description of a new species

Vietnam is a large country of Southeast Asia and a globally recognized hotspot of biodiversity. Until recently, only limited surveys had been carried out on the resident Phytoseiidae fauna and presence of 12 species had been documented, with 11 belonging to the sub-family Amblyseiinae and 1 to the sub-family Typhlodrominae. Here, we present results from 2017 field surveys and add a total of 8 new country records, one of which a newly-described species. At least 5 species (i.e., Neoseiulus longispinosus, Paraphytoseius cracentis, P. orientalis, Amblyseius cinctus and A. herbicolus) are well-known biological control agents (BCA), while two species (Euseius ovaloides and Gynaeseius liturivorus) carries ample potential as BCA agents but necessitates further study. In addition to the intrinsic value of phytoseiid mite biodiversity in tropical environments, demonstration of the natural occurrence of efficient BCAs in Southeast Asian countries such as Vietnam is of great agricultural and commercial interest.

Evaluation of prey stage preference of the predatory mite Neoseiulus longispinosus (Evans) on the spider mite pest Tetranychus neocaledonicus (André) (Acari: Phytoseiidae, Tetranychidae)

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.