Red Spider Mite
The red-spider mite loves warm airless conditions and will thrive in the greenhouse.
The mite is extremely small and will not often be spotted even though it infests in great numbers. It is the fine web that it weaves between the leaves and the damage it causes to them that is the giveaway. They will become pale and limp, sometimes almost dirty with a bronze discolouration before they fall. The obvious solution is to spray the undersides of the leaves but by this time much of the damage has been done. If the plant is in a pot under glass, move it outside for a while and spray it with water occasionally; the spider mite will not enjoy its new habitat and will move away to a more appropriate area or die.
