A. Investigation on species of key pests and natural enemies in paddy and orchard

Based on the specialty of local agricultural products, the investigation were done in rice paddies in Ceroh tribe, Yuli, Hualien (Fig.1A) and in pomelo orchards in Olalip tribe, Ruisu, Hualien (Fig.1B).

1. Rice paddies in Ceroh tribe

There were 3 organic and 3 conventional investigation paddies (Fig.1A), and each of them was at least 0.3 hectare. Each paddy was divided into several 100m2 (10m×10m) area, and we randomly chose 3 areas to do the sampling. The investigation underwent 5 growth stages of rice including transplanting, tillering, booting/heading, milky/doughy and yellow ripe stage. During the transplanting stage, we sampled the insects by yellow sticky traps on ridges. In other stages, despite the traps, we also walked into paddies and collected insects by sweeping net (Fig.2). Brought back the collected samples and sticky traps then examined by stereomicroscope (Leica, Germany). The targets of key pests were planthoppers (Delphacidae), leafhoppers, leaffolders (Cnaphalocrocis medinalis) and stem borers (Chilo suppressalis). The natural enemies were ladybugs (Micraspis discolor), spiders (Tetragnathidae), parasitoid wasps (Ichneumonid, Braconidae, Trichogrammatidae, Pteromalidae, Eulophidae and Mymaridae), Empididae and Ochthera sp.

2. Pomelo orchards in Olalip tribe

There were 3 organic and 3 conventional investigation orchards (Fig.1B), and each of them was at least 0.3 hectare. Each orchard was also divided into several 100m2 (10m×10m) area, and we randomly chose 3 areas to do the sampling. The investigation underwent 6 growth stages of pomelo including differentiation of flower bud, flowering, fruiting (small, medium and large) and fallow stage. In each sampling area, we collected the insects by beat netting one pomelo tree (Fig.3), and put yellow sticky traps on grass beneath. Brought back the collected samples and sticky traps then examined by stereomicroscope (Leica, Germany). The targets of key pests were thrips, aphids, flies and stinkbugs. The natural enemies were Anthocoridae, hover flies (Syrphidae), lacewings (Syrphidae), ladybugs (Coccinellidae), parasitoid wasps (Braconidae, Chalcididae, Eupelmidae, Scelionidae and Ichneumonid) and spiders.

B. Lifespan assay of natural enemies on aboriginal plants

To enrich ecological diversity and create a suitable environment for beneficial natural enemies are the suggested ways to regulate and control pests. At the same time, we can possibly reduce the usage and cost of chemical pesticides. By creating habitat with specific aboriginal plants on ridges and bared land in pomelo orchards, we hoped to increase the numbers and species of beneficial natural enemies. The plants were preliminary screened and chosen by cultivation traits, flowering season, adaptability to the weather, and abilities or duration time to provide nectar. These aboriginal plants were kept in and provided from Lanyang branch. And then we grew them in the greenhouse in Hualien for experiment. Finally 13 species were chosen and including herbal plants Anster indicus L., Mesona chinensis, Gonostegia hirta (Blume) Miq., Wedelia chinesis (Osbeck) Merr., Houttuynia cordata Thunb., Phyla nodiflora (L.) Greene. and Indigofera spicata Forsk., which were grown in 3 inches pots, and woody ones Vitex trifolia Linn., Vitex negundo L., Cajanus cajan (L.) Huth., Zanthoxylum ailanthoides, Hibiscus syriacus L., and Callicarpa formosana, which were grown in larger pots. All the experimental plants were kept to the flowering stage and the assay was done by that time.

1. Lifespan assay of parasitic natural enemy

Dirhinus giffardii (Hymenoptera: Chalcididae) (Fig.4) were reported having great effects on controlling fruit fly (Bactrocera dorsalis) in orchards in Taiwan. In our research, D. giffardii was the representative species of parasitic natural enemy. The eggs were kindly provided by Miaoli DARES. 3 days after the insects hatched, we put one mature female D. giffardii on the assay plant and observed its survival time. The experimental groups were plants with flowers or not, and the control group was only water provided. This year we did the assay on 10 plants except V. negundo, Z. ailanthoides and H. syriacus. In case of escaping of insects, the herbs pot were put in the PET cup (11.7cm in bottom diameter) and cover the lid with 30 cm 100-mesh net on it (Fig.5). The woody plants were covering by 71×48 cm (L×W) 100-mesh net.

2. Lifespan assay of predacious natural enemy

Ladybug Cheilomenes sexmaculata (Coleoptera) (Fig.6) were the representative species of predacious natural enemy. This ladybug was the product from Good Farms Co., Ltd. The experimental groups were plants with flowers or not, and the control group was only water provided.