For integrated pest management（IPM）of strawberries in Miyagi Prefecture, Japan, combinations of applications of Phytoseiulus persimilis Athias-Henriot, Neoseiulus californicus（McGregor）, spiracle-blocking insecticides, fumigation using a high concentration of carbon dioxide, and an increase in UV-B radiation using a reflective sheet are currently in use for the control of spider mites. Efforts are underway to improve and expand on these methods. For the control of aphids, application of two natural enemies, Aphidius colemani Viereck and Ephedrus nacheri Quilis, in conjunction with banker plant system is highly effective, and their use is expected to increase over the next few years. For the control of thrips, application of selective pesticide at the initial time of their occurrence after installing red insect-proof nets（mesh size 0.8×0.8 mm）around the opening of the greenhouse is currently used. The possibility of using natural enemies against thrips, such as Haplothrips brevitubus（Karny）, Amblydromalus limonicus（Garman et McGregor）, and Amblyseius cucumeris（Oudemans）, needs further study. For the control of whiteflies, a tape formulation of pyriproxyfen and spiracle-blocking insecticides, as used in the control of spider mites, can maintain populations at a low density. Although there are difficulties in the use of entomopathogenic fungi and indigenous natural enemies due to the cold climate, we need to further examine their efficacity as IPM.
We investigated the vegetation management and occurrence of two mirid bugs, Trigonotylus caelestialium（Kirkaldy）（Hemiptera: Miridae）and Stenotus rubrovittatus（Matsumura）（Hemiptera: Miridae）, causing pecky rice, in rice paddy levees over an area measuring 10 ha in Niigata Prefecture, Japan. Mowing and herbicide application were carried out on the levees several times to manage weeds during the growing period of rice. Major poaceous plants on the investigated levees were Poa annua, Alopecurus aequalis, Digitaria ciliaris, and Echinochloa crus-galli. The two mirid bug species existed either separately or together on levees infested with ear-emerged poaceous plants. In July and August, which are important periods for forecasting the two bugs, D. ciliaris was the major plant and occurrence of the two mirid bugs was almost entirely restricted to the levees infested with ear-emerged D. ciliaris. Ears of D. ciliaris vanished after mowing or herbicide application and re-emerged with growth. As a result, the locations of levees infested with ear-emerged D. ciliaris changed over short periods. The observation results were similar over 3 years, and there were no significant changes in weed management, vegetation, and occurrence of the two bugs in the area. In levees infested with ear-emerged D. ciliaris, the spatial distribution pattern of T. caelestialium was aggregated, and that of S. rubrovittatus was even more aggregated. Despite the difference in the distribution, the locations and areas of levees infested with ear-emerged poaceous plants could be used in indices for regionally forecasting the occurrence of the two bugs.
We investigated the effects of abiotic environmental factors on spring flight initiation of Scirtothrips dorsalis Hood（Thysanoptera: Thripidae）by monitoring the number of its overwintered adults captured by yellow sticky traps in a Japanese pear orchard from 2012 to 2015. More S. dorsalis were captured on sticky traps placed at 50 cm above ground level in the plot where pear trees were dense than in the plot where trees were sparse, which suggests that many adults overwintered inside of pear orchards. More S. dorsalis were captured on traps placed at 50 cm above ground level than at 200 cm above, which suggests that sticky traps at 50 cm above ground level were suitable for monitoring the overwintered generation of S. dorsalis. A logistic regression analysis revealed that the capture probability（Pc）of overwintered adults was positively correlated with the daily maximum temperature and the hours of sunlight, and negatively correlated with the daily mean wind speed. More than 99% of S. dorsalis were captured when the maximum temperature exceeded 17.5°C, the mean wind speed was ≤2.7 m/s, or sunlight was ≥3.7 h/d. The date of peak capture of overwintered S. dorsalis could be estimated more accurately from the total effective temperature calculated from January 1 combined with the Pc value than from the total effective temperature alone.
The olive weevil, Pimelocerus perforatus（Roelofs）（Coleoptera: Curculionidae）, is a serious pest of olive cultivation in Japan. Although male and female adults of weevils are generally very similar, we established a simple method for discriminating the sex of olive weevil adults based on external morphology. We found that the first through fourth abdominal ventrites of the females were longer than those of the males, while the fifth abdominal ventrite was shorter. Moreover, the length of the lateral margin of the second abdominal ventrite was markedly different between the sexes. As a result, the ratio of the medial length of the fifth abdominal ventrite to the lateral margin length of the second abdominal ventrite was distinct between the sexes in both wild and laboratory-reared populations of P. perforatus, i.e., the ratio was larger than 0.60–0.65 in females but smaller in males. In addition to this characteristic, the structure of the medial part of the first abdominal ventrite differed between the sexes: it was depressed in the middle in males but inflated in the middle in females. Based on these morphological differences, males and females of the olive weevil were successively discriminated from each other.