Scale Insect is difficult to spot and can easliy increase unnoticed and will affect plants both underglass and outside in the summer. Outside, keep a close eye on Japenese acers, camellias, rhododendrons, azaleas and box. Underglass, scale is very partial to citrus. Control scale insect BOTH outdoors and under-glass by spraying with Scale Nematodes. Scale Nematodes need a daytime temperature of 14C, so spray OUTDOOR plants in the summer when the temperature is above 14°c. Potted OUTDOOR plants can be treated outdoors when the temperature is above 14°c or they can be moved into a greenhouse or conservatory to treat. Spray INDOOR plants (in conservatories and geenhouses) with scale nematodes ANYTIME scale is discovered and the temp is above 14c.