Is the disease issue the only advice you are seeking? As to the disease issue - would wilting be a suitable description? Where in the world are we talking about? Is it possibly a heat/water stress situation. The problem with wilt is that it could be too much water, not enough water, fungal, bacterial or insect related. Understanding possible disease vectors and how the onset occurred can be essentially important in diagnosing the problem.
https://www.echocommunity.org/ Is an agriculturally focused aid community, which might be worth investigating, I have found their resources to be helpful in the past.
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