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.

Statistik Demografi Kumbang Predator Stethorus sp. (Coleoptera: Coccinellidae) pada Tetranychus Kanzawai Kishida (Acari: Tetranychidae)

Tetranychus kanzawai Kishida adalah spesies tungau yang dapat menyebabkan kehilangan hasil pada tanaman pertanian sekitar 60–90%. Salah satu cara untuk mengendalikan tungau hama yang ramah lingkungan adalah dengan menggunakan kumbang predator Stethorus punctillum Weise. Penelitian ini bertujuan untuk menentukan statistik demografi, preferensi, dan tanggap fungsional S. punctillum pada T. kanzawai. Pengujian neraca hayati S. punctillum menggunakan 100 telur, dengan mengamati jumlah individu yang masih hidup sampai betina dewasa menghasilkan keturunan. Preferensi S. punctillum terhadap 50 telur dan 50 individu masing-masing nimfa dan imago T. kanzawai, dengan mengamati jumlah T. kanzawai yang dimangsa oleh larva instar I, II, III, IV dan imago S. punctillum. Tanggap fungsional dilakukan dengan memberi mangsa S. punctillum sebanyak 30, 40, 50, 60, 70, 80 telur T. kanzawai, pengamatan dilakukan pada jumlah telur yang tersisa. Hasil penelitian menunjukkan bahwa telur S. punctillum berlangsung selama 7,01 ± 0,72 hari, larva instar I 4,84 ± 0,51 hari, instar II 3,16 ± 0,52 hari, instar III 3,00 ± 0,27 hari, dan instar IV 2,48 ± 0,50 hari. Kemampuan betina menghasilkan telur sebanyak 64,47 ± 2,37 butir. Laju reproduksi kotor (GRR) S. punctillum 64,29 individu/generasi, tingkat reproduksi bersih (Ro) 17,18 individu/betina/generasi, laju pertambahan intrinsik (r) 0,27 individu/betina/hari, rata-rata masa generasi (T) adalah 62,41 hari, dan waktu ganda (DT) adalah 2,51 hari. Data menunjukkan bahwa S. punctillum memiliki preferensi stadia telur T. kanzawai dan kurva tanggap fungsional tipe III dengan Th 7,68 menit dan a 0,22 telur/menit.

Updated and annotated review of Tetranychidae occurring in mainland Portugal, the Azores, and Madeira Archipelagos

Data on the diversity, distribution, and main hosts of spider mites (Acari: Tetranychidae) are scarce in the Iberian Peninsula, particularly for Portugal, where only 21 species are recorded on the mainland and in the Azores and Madeira archipelagos. Moreover, the scientific information is mainly available in national publications, and difficult to access for international researchers. In this paper, we review the literature dealing with spider mites in mainland Portugal and the archipelagos of the Azores and Madeira, compiling and synthesizing the most relevant information on their distribution, hosts and pest potential. Further information was obtained by verifying slides in the acarological collection of the Instituto Nacional de Investigação Agrária e Veterinária (INIAV), the most important national collection, and by verifying mites collected on different plant hosts during the period 2018-2020. In total, we found records for 28 spider mite species in Portugal, comprising nine Bryobiinae and 19 Tetranychinae, and including new national records for Stigmaeopsis nanjingensis and Eotetranychus tiliarium. Additionally, we record a new exotic mite species for the mainland, Eotetranychus lewisi, which was found in two localities in the Algarve District on leaves of Euphorbia pulcherrima. This is the first record for continental Europe of an established population in outdoor conditions of this regulated quarantine pest. We also comment on the presence of seven species not reported by international taxonomic databases but already recorded from Portugal: Aplonobia histricina, Eotetranychus rubiphilus, Schizonobia sycophanta, Tetranychus kanzawai and Tetranycopsis horridus (at a national level), and Oligonychus perseae and Panonychus citri (for the mainland). New host records are given for Bryobia praetiosa, Petrobia (Tetranychina) harti, S. sycophanta, E. coryli, E. rubiphilus, Tetranychus kanzawai, Tetranychus lintearius, Tetranychus ludeni and Tetranychus turkestani.

Oviposition-site shift in phytophagous mites reflects a trade-off between predator avoidance and rainstorm resistance

Predators can reduce prey population densities by driving them to undertake costly defences. Here, we report on a remarkable example of induced antipredator defence in spider mites that enhances the risk to rainstorms. Spider mites live on the undersides of host plant leaves and usually oviposit on the leaf undersurface. When they are threatened by predatory mites, they oviposit on three-dimensional webs to avoid egg predation, although the cost of ovipositing on webs has not yet been clearly determined. We prepared bean plants harbouring spider mite ( Tetranychus kanzawai ) eggs on either leaf surfaces or webs and exposed them to rainstorms outdoors. We found that fewer eggs remained on webs than on leaf surfaces. We then examined the synergistic effect of wind and rain by simulating both in the laboratory. We conclude that ovipositing on webs comes at a cost, as eggs are washed off the host plants by wind and rain. This may explain why spider mite populations decrease drastically in the rainy season, although they inhibit leaf undersides where they are not directly exposed to rainfall.

Two New Records for Spider Mite Fauna of Turkey, Tetranychus kanzawai Kishida and Eotetranychus rubiphilus Reck (Trombidiformes: Tetranychidae)

Two new spider mites, Tetranychus kanzawai Kishida and Eotetranychus rubiphilus Reck (Trombidiformes: Tetranychidae) were recorded for Turkish phytophagous mite fauna. While E. rubiphilus was obtained from Prunus domestica L. and Prunus cerasus L. (Rosaceae), T. kanzawai was found only on P. domestica in different municipalities of Ordu province, Turkey.