Since 2006, we have worked on the establishment and dissemination of an Integrated Pest Management（IPM）program in cooperation with agricultural extension officers, related research organizations, and IPM product companies in Japan. Today, 12 years have passed, and the use of IPM with biological control agents（BCA）has spread to many agricultural production sites. Dissemination and extension activities of IPM were promoted not only in the greenhouse cultivation of tomatoes, strawberries, sweet peppers, cucumbers, eggplants, melons, watermelons, ornamentals, and citruses, but also spreading to eggplants in the open field from 2015. As a result, in strawberries, sweet peppers, eggplants, cucumbers, and citruses grown in greenhouse, IPMs, which are mainly used by natural enemies as the main BCA, are considered to have increased dramatically due to the following three major contributions. 1）For a stable and successful IPM program, it was important to let the natural enemy density grow before increasing pest insects by using generalist predatory mites, such as Neoseiulus californicus and Amblyseius swirskii. 2）Demonstration tests were conducted in which extension officers planned, verified, and evaluated with the growers, which led to an improvement in their knowledge and skills. 3）As we conducted multifaceted demonstration tests in Japan, the sharing of information on the techniques of using IPM programs has progressed in a short period of time. However, for tomatoes, ornamentals, melons, and watermelons, a lack of solution tools against disease control and the cost performance of control programs have been issues, and the use of IPM programs is becoming less popular. In order to establish IPM techniques, we think it is important to conduct dissemination activities for showing the benefits of IPM leading to problem-solving for each region and grower, and for growers to recognize the merit of selecting IPM.
Bradysia odoriphaga Yang and Zhang（Diptera: Sciaridae）was discovered in the Welsh onion fields of northern Saitama in 2014 and the carrot fields of northern Saitama in 2015, and later in Chinese chive fields in central Gunma Prefecture. Elucidation of the dispersal ability of B. odoriphaga is important for its control. We investigated the flight and walking activities of B. odoriphaga and B. impatiens（Johannsen）. The flight and walking durations of adults at 16, 19, 24, and 30°C were investigated by video recording. The flight duration of B. odoriphaga was significantly shorter than that of B. impatiens. In females of B. odoriphaga, the longest continuous flight duration was 2.4 seconds. The walking durations of male B. odoriphaga adults and both sexes of B. impatiens adults were not affected by temperature. In females of B. odoriphaga, the walking durations at 19 and 16°C were significantly shorter than those at other temperatures. Our results suggest that the range of B. odoriphaga dispersal is narrow.
To estimate the damage risk and select control methods for the soybean pod borer, Leguminivora glycinivorella（Matsumura）（Lepidoptera: Tortricidae）, over 200 soybean fields cultivated by farmers and treated with insecticides 0–2 times for the borer were surveyed in Niigata and Nagano Prefectures from 2015 to 2018. A decision tree analysis was performed on the non-treated data. The tree-model had four terminal nodes and was split by three factors: soybean continuous cropping year, damage rate in the previous year, and distance to the nearest field where soybeans were cropped in the previous year. The four terminal nodes were ordered from low to high according to the damage level of the fields classified to each node. The order of nodes did not differ between the modeling data and test data, which were data from other uncontrolled fields. As the number of insecticide treatments increased, the ratio of low-damage-level fields increased to ＞90% in all terminal nodes except the highest-damage-level node. These results indicate that the order of the four terminal nodes may represent the order of damage risk. The tree-model may enable rational selection of the number of insecticide treatments or rotation of soybean to rice before planting.
Cletus punctiger（Dallas）（Heteroptera: Coreidae）is widely distributed in Japan. This insect is a serious pest that sucks developing rice kernels and causes pecky rice. Adults collected in environmental fields, orally acquire symbiotic bacteria belonging to the genus Burkholderia from environmental soil in the nymphal stage and commonly possess the symbionts in their gut crypts. Therefore, we examined whether nymphs reared with food, water and soil collected from their natural habitat acquire the symbionts. Rearing experiments with soil demonstrated that nymphs acquire the symbionts. We then investigated the developmental zeros and effective accumulative temperatures using rearing experiments with food, water, and soil. The developmental zeros were 14.3°C in the egg stage, and 14.0°C and 14.1°C from the egg to the nymph stage in the females and males, respectively, and 12.8°C in the preoviposition period. The effective accumulative temperatures were 84.0 day-degrees in the egg stage, 344.8 day-degrees from the egg to the nymph stage in both females and males, and 131.6 day-degrees in the preoviposition period. Based on the data above, the number of annual generations of C. punctiger in Shiga Prefecture was estimated to be three at the most. The new adults in the third generation are considered diapause adults that move to hibernating sites.
Two isolates of Beauveria bassiana（Balsamo-Crivelli）Vuillemin and one isolate of Isaria fumosorosea Wize were isolated from Diaphorina citri Kuwayama（Hemiptera: Liviidae）, a vector of huanglongbing（citrus greening disease）. The ability of these isolates to kill D. citri, two Cacopsylla species（Hemiptera: Psyllidae）, and the brown citrus aphid, Toxoptera citricida（Kirkaldy）, and the effect of temperature in vitro on their growth were investigated. Infection with all three isolates resulted in high mortality for D. citri. In the Cacopsylla spp. and T. citricida, some isolates caused consistent mortality, but this varied among isolates. Mycelial growth of the three isolates was vigorous at 20–30°C. The two isolates of B. bassiana grew well at 25°C, while the I. fumosorosea isolate grew well at 25–30°C, indicating that the optimal growth temperature varied among the isolates.
The activity of male diamondback moths, Plutella xylostella（L.）（Lepidoptera: Plutellidae）, under LED lighting（450, 470, and 525 nm）during the dark phase of a 14L : 10D photoperiod was examined for 5 days. Under the 14L : 10D condition, males showed high activity in the dark phase. However, under 450 and 470 nm LED lighting, the activity was inhibited, as with a 24L : 0D photoperiod. The number of fertilized eggs laid under 450 and 470 nm LED lighting during the dark phase of a 16L : 8D photoperiod was significantly lower than under normal conditions. Furthermore, the lowest percentage of females laying fertilized eggs was observed under 450 and 470 nm LED lighting.