To estimate the infection source of mango stem-end rot, we investigated the temporal changes in the occurrence of stem-end rot of mango fruit clusters. We also examined the habitat distribution and conidial dispersal of the causal fungus, Lasiodiplodia theobromae from lesions in diseased fruit clusters under greenhouse cultivation. Occurrence of stem-end rot in fruit clusters increased after anthesis in March and peaked during the harvest period in July. Conidial dispersal fluctuated markedly from May to July, with vigorous dispersal occurring from mid-to late June. Lasiodiplodia theobromae was isolated at high rates from flowers, peduncles, fruit-bearing shoots, and fruiting mother shoots, indicating extensive latent infection in a diseased field. We assumed that the main infection sources of this disease are infected fruit clusters and conidia from lesions on infected fruit clusters. We subsequently investigated the efficacy of removing dead branch residues in greenhouses to prevent the spread of disease. We found that occurrence of the disease in fruit clusters was significantly lower for branch-removal plots relative to the untreated control. Specifically, incidence of the disease in branch-removal plots was reduced to 31.1-56.0% of that in the untreated control during anthesis and 32.5-38.8% during the harvest period.
The effect of the pesticide, buprofezin, supplemented with paraffin was tested on the adult hibernating stage of scales, Pseudaulacaspis prunicola and Pseudaulacaspis pentagona. Pre-emergence treatment of buprofezin supplemented with diluted paraffin was more effective than machine oil in suppressing P. prunicola on plum. In an open-field culture of kiwi, this treatment was more effective than only buprofezin, and a 500×dilution was more effective than a 1,000×dilution of supplemented paraffin on ? ? ? ? ?. On peach, on which both ? ? and ?? ? ? occur, buprofezin supplemented with paraffin indemnified against dead branch than that supplemented with machine oil. Thus, these pre-emergence treatments of buprofezin supplemented with paraffin were effective in suppressing the densities of both ? ? and ??? ?. None of the treatments tested caused any crop injury.
Anagyrus fujikona Tachikawa is a major parasitoid of the Japanese mealybug Planococcus kraunhiae (Kuwana), a pest of the Japanese persimmon, and uses the hostsʼ sex pheromone as a kairomonal cue for foraging behavior. Thus, mating disruption against the host using its synthetic pheromone may potentially affect the waspʼs behavior. Here, however, we did not find significant decrease of the A. fujikona parasitism in plots with the mating disruption treatment against P. kraunhiae in a persimmon orchard, suggesting that there is no evidence of adverse influence of the mating disruption on the activity level of the indigenous natural enemy.
果樹の重要害虫であるチャバネアオカメムシ（Plautia stali SCOTT）累代飼育虫（23℃， 16L8D）を用いて産卵およびふ化に対する高温の影響を調査した。羽化後35℃で飼育した雌成虫は，25℃で飼育した場合に比べ生涯産卵数は少なく，その卵はふ化しなかった。また，５齢幼虫の期間のみ35℃におくと全期間23℃で飼育した場合に比べ生涯産卵数は少なく，そのふ化数も少なかった。以上のことから35℃の高温は，チャバネアオカメムシの産卵およびふ化に悪影響を及ぼすと考えられた。
In burdock, root feeding damage caused by Scepticus uniformis Kôno larvae which inhabit the soil significantly reduces the commercial value. However, there is no registered insecticide in the seed furrow treatment for the control of the weevil larvae. Therefore, the registration of clothianidin granules in the seed furrow treatment is expected. Accordingly, we examined the control effects by application depth in soil treatment of clothianidin granule of 6kg per 10 ares for S. uniformis on burdock for two years. As a result, the application of the insecticide at 2cm in depth and that at 5cm respectively reduced the root damage, compared with the application at 10 cm in depth in the first year and plant foot application in the second year. Consequently, it is considered that the application at 2-5cm in depth is effective in the soil treatment of the insecticide for the control of the weevils on burdock.
To establish effective control against thrips which damages broad bean in open field cultivation, inoculative release of predatory mite, Amblyseius swirskii Athias-Henriot, was evaluated under greenhouses and open field conditions from October to December in Kagoshima, Japan. The dominant species of thrips was Thrips hawaiiensis（Morgan） in this present study. Population densities of thrips when A. swirskii was released were significantly lower than non-treatment trial under the both conditions; greenhouses and open field cultivation. The timing of release before or during blooming period and releasing method with bottles or resin bags of predatory mites affected significantly the densities of thrips or predatory mites on broad bean. We might use A. swirskii successfully by releasing ones with bottles before blooming of broad bean. Furthermore, alyssum as insectary plants was considered to be effective to enhance the population growth of A. swirskii on broad bean.
In this study, we devised a new application for the control of Tetranychus urticae Koch, which infests strawberry plants, by dipping stems and leaves of strawberry plants in a 300-fold diluted solution of formulation oil prior to transplanting in the field（dipping treatment）. The efficacy of this dipping treatment against T. urticae was evaluated by laboratory tests and field tests. In laboratory tests using kidney beans , the corrected mortalities of adult females, nymphs, and eggs by the dipping treatment were 100%, 100%, and 93.7%, respectively. In the field tests conducted in 2017 and 2018, the population densities of T. urticae decreased by the dipping treatment in formulation oil. Further, compared to a chemosynthetic insecticide treatment, population densities of T. urticae were significantly suppressed for a prolonged period by additionally releasing the phytoseiid and spraying formulation oil on strawberry plants after the dipping treatment. This combination treatment had no effect on the growth and terminal flower bud emergence rate of strawberry. Thus, our findings suggest that this treatment effectively controls T. urticae.
We evaluated the effects of seven granular insecticides on the population density of Thrips nigropilosus Uzel occurred on chrysanthemum cultivated in a greenhouse. In our study, acephate, carbosulfan（organophosphate）, benfuracarb（carbamate）, acetamiprid, clothianidin, imidacloprid, and nitenpyram（neonicotinoid） were applied to the soil at the recommended dose（0.3 g, 1.0 g, or 2.0 g / plant） immediately after planting. The number of the thrips on chrysanthemum was investigated on 0, 6, 13, 20, 27, 33, and 41 days after applications. Our results indicated that all the seven insecticides were effective against T. nigropilosus though efficacy and its duration were significantly different among insecticides. Benfuracarb was shown to be the most effective insecticide for suppressing the density of the thrips.
Scirtothrips dorsalis Hood is known as one of the most important pest of mango plants cultivated in greenhouse in Kagoshima Prefecture. S. dorsalis has two strains, C and YT. Strain C have also found in Kagoshima prefecture mango cultivated in 2009. But, there is little information about their seasonal prevalence of strains C and YT on mango cultivated. In this study, the seasonal prevalence of both strains adult caught by yellow sticky traps in mango cultivated was investigated from August 2011 to December 2015. Strains were analyzed by a multiplex-PCR method. Both strains were started to increase after February, and had two peaks from March to April and from August to October. These were synchronously with stage of flowering and new branch growing. However, Strain C was continuously found in autumn and winter, while strain YT had not been found at the end of October at the latest. In addition, the number of strain C has tendency to increase due to the decreased control effect of neonicotinoids.