Any grower who has suffered an onslaught of whitefly will have struggled to control them with pesticides either because of poor under-leaf spray cover or pesticide resistance. Only the whitefly larvae and adults stages are susceptible to pesticides. The eggs and pupae are not actively feeding and are therefore left unscathed by this chemical assault. Resistance of whitefly to pesticides is an inevitable outcome of an intensive spray programme, because there are too few insecticides from different IRAC groups to prevent this happening. (See attached whitefly pesticides chart).

Spider mite is the bane of flower growers throughout the world, from the high tech, top of the range greenhouse growers to the outdoor summer flowers of small-scale flower growers trying to earn a reasonable living. If mites are not controlled, they represent a serious threat to many flowers including roses, carnations, alstromeria, chrysanthemum, particularly if the crop is grown under greenhouse conditions or in all year round growing conditions. Miticides can account for 50% of the pesticide budget on an annual recurrent basis – and still they come back each year. With all year round greenhouse production, there is less of a respite in the Northern and Southern hemisphere growing regions, where growers used to have some relief during the winter months as the spider mites went into hibernation.

Mealybugs suck the life sap from crops, and in the process they will ooze a sticky solution over the upper surfaces of leaves below their feeding sites. This soon becomes a black sooty mess, as fungi grow on the sugary solution.

A study to better understand the optimum conditions for Easter lily bulb production makes a preference for scale bulblets and suggests bulbs can be grown in a controlled environment.
by Paul Nelson, Carl Niedziela, Seung-Hyun Kim, and August De Hertogh