Research for Tropical Agriculture
Online ISSN : 2187-2414
Print ISSN : 1882-8434
ISSN-L : 1882-8434
Volume 11 , Issue 2
Showing 1-9 articles out of 9 articles from the selected issue
Original Article
  • Tetsuya TAKUSHI, Atsushi AJITOMI, Chiemi ARASAKI, Atsushi OOSHIRO, Sat ...
    2018 Volume 11 Issue 2 Pages 43-52
    Published: 2018
    Released: August 20, 2019

    In order to develop an effective common control management for stem-end rot and anthracnose disease of mango based on fungicides, we evaluated the sensitivity of registered fungicides to the causal fungi of two diseases, and the efficacy of a systematic application of fungicide combinations during the active growth period of mango. Of the 10 registered fungicides tested, five (mancozeb wettable powder, azoxystrobin flowable, kresoxim-methyl dry flowable, basic copper sulfate wettable powder, and captan wettable powder) were found to have a high inhibitory effect on the conidial germination and mycelial growth of the causal fungus of stem-end rot, Lasiodiplodia theobromae, and two causal fungi of anthracnose, Colletotrichum siamense and C. fioriniae. In contrast, mepanipyrim flowable, iminoctadine albesilate acid chloride wettable powder and triflumizole wettable powder had no inhibitory effects on this fungus. The two causal fungi of anthracnose showed different sensitivity to iprodione wettable powder, mepanipyrim flowable, triflumizole wettable powder and iminoctadine albesilate acid chloride wettable powder in the inhibition of conidial germination. In the field trials conducted in two fields between 2012 and 2014, various combinations of the five fungicides that exhibited high in vitro antifungal activity against all three causal fungi were systematically applied between apical bud formation or flowering and pre-harvest (prior to bagging). During those years, these fungicide combinations exhibited stable protection against post-harvest fruit damage caused by either disease. Although phytotoxicity due to the systematic application of fungicides was observed in 3.2% of fruit in the 2013 trial, it was not observed in either 2012 or 2014. The meta-analysis of the five trials conducted over the three-year period revealed that the incidence of both diseases decreased significantly in mango fruit, receiving systematic fungicide application compared to untreated mango fruit, to approximately 24% and 23% of the incidence in untreated fruit for stem-end rot and anthracnose, respectively. The results above demonstrate that the systematic application of fungicide combinations is an effective means for controlling stem-end rot and anthracnose disease of mango.

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  • Haruyuki DAN, Yoko OKI, Shinji HIROUCHI
    2018 Volume 11 Issue 2 Pages 53-59
    Published: 2018
    Released: August 20, 2019

    The conversion of rain-fed rice cultivation into irrigated-rice cultivation is considered to be one measure for increasing rice productivity. Thus, the development of paddy fields in the inland valleys of Ghana has been promoted. However, irrigation facilities have not been functioning satisfactorily due to a high intensive rainfall and poor maintenance. In this paper, a list of characteristics, required for cover plants, was made prior to the introduction of reinforcement technology to irrigation facilities, utilizing them. Moreover, an example of the evaluation of coverability, that is required in all parts of the irrigation facilities and is emphasized in this research, was shown based on the results of the test cultivation. In the test of the vegetation-coverage rate, judgement criteria were set, based on soil conditions and were used to measure it in four test plants. The adaptability of these plants for the introduction as cover plants was evaluated under three different growth environments in fine gravel content, soil hardness and volmetric water content. In the cultivation test, the amount of growth of test plants was clarified by calculating their Leaf Area Index. Furthermore, the appropriate timing and intervals for important vegetation management work after planting such as weeding, were considered. The chlorophyll contents of the test plants were confirmed to have the same tendency as the results of the Leaf Area Index, based on their SPAD values across a one-year period. The results of these tests can be used by farmers when making decisions concerning adopting this technology.

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