[quote=Lintama;846738]OK Thank you Lannerman. I had a friend tell me it could be lack of nitrogen. Could this be the problem instead? I am not saying you are wrong of course, just trying out possibilities.

Hi, Lintama, Lack of nitrogen will not give you the 'mottled' effect you discribed just an overall yellowing, but I thought you said you had fed them?
Try the dithane anyway as I'm sure this will clear the problem, and it will not do any harm to give them a liquid feed again as they are quite hungry.
best wishes lannerman.