Finding the Greenhouse Whitefly in the dark

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The greenhouse whitefly is a pest. While they seem harmful in small numbers, it will be only a matter of time until they lay eggs and rapidly expand their population. Worse, when the greenhouse whitefly drops their larvae inside a leaf and that larvae digs through the subsurface of the leaf eating its way through and leaving behind what looks like squiggly lines on the leaf.

Greenhouse Whitefly

The greenhouse whitefly (Trialeurodes vaporariorum) feeds on a variety of vegetable and floral crops. Whiteflies suck the juices out of the leaves, causing a lack of vigor and eventual wilting. They also secrete a sticky material called honeydew, which results in a black fungus (sooty mold). Sooty mold can eventually cover an entire leaf then interferes with the plant’s photosynthetic processes by reducing its vigor and eventually causing premature plant death.

Females whiteflies lay 150 or more eggs on the underside of leaves, at a rate of about 25 per day. Hatching occurs within 10 days. After hatching, the nymph digs through the leaf while feeding on plant tissues to complete the following stages of development. Usually when you start to notice whiteflies, it’s already too late and the damage has been done.

Since they are so small too see when in small numbers, there’s an easy method we use to identify the greenhouse whitefly after the sun sets. Early detection and the appropriate early response can save your high value crops.

In one grow trial, we observed an entire infestation of whiteflies decimate our bell pepper crops. Once the sooty mold was visible, it was too late as the whitefly population had expanded into an infestation.

UV Blacklight

A simple, inexpensive blacklight illuminates various pests including the greenhouse whitefly when shining the underside of a leaf. You’ll be able to spot them much easier than during the day, especially since they are more active during the day. Once you identify a few whiteflies on a leaf, you have to act fast and remedy the situation before those few turn into a full blown infestation. 

Using a blacklight, you can spot the whiteflies easily in the dark

Portable Aluminum 21LED UV Ultra Violet Blacklight Flashlight Torch Light Lamp