Angular leaf spot
The disease is found in conditions if high humidity, especially in poor ventilated greenhouses or where the ventilation is not controlled properly. Optimum temperature for...
Category Archives: Crop protection
Crop protection is crucial to long term profitability of a commercial hydroponic farm. You need to know which chemicals to apply at the right time to ensure a high percentage of grade a product.
Basic pest and disease resistance management strategies in greenhouses
Resistance to chemicals is due to the intense selection pressure exerted on the population that is controlled. There is only a limited number of chemicals...
Tipburn in lettuce
Tipburn in lettuce has been a problem since the first farmer planted lettuce. Any grower will at some stage have the problem occur to some...
Lettuce deficiency and toxicity symptoms of macro and micro elements
It is often quite difficult to identify a deficiency or toxicity symptom in the field because they never really occur as a single element deficiency...
Onion thrips
Description Thrips tabaci and western flower thrips Frankliniella occidentalis are sap feeders. Common thrips as in the main image; Order: Thysanoptera, Family: Thripidae. They are...
Tomato russet mite
Description Russet mites (Aculops lycopersici, Aculus lycopersici) are so small that a 14X hand lens is needed to see them. Because of their size, these...
Plusia looper
Plusia looper description Plusia looper, also known as Cabbage looper or more correctly Trichoplusia ni are light green caterpillars with white or pale yellow stripes...
American Bollworm
Bollworm description Bollworm, also known as tomato fruit worm or American Bollworm, Helicoverpa armigera, are small caterpillars (about 30mm long, slightly more than 1 inch)...
Common physiological disorders in cucumbers
Physiological disorders caused by low temperatures Low temperatures injury only occurs with fruit that are in storage (either in transit or in storage rooms). Small...
Sweet potato whitefly
Sweet potato whitefly description Sweet potato whitefly (Bemisia tabaci, order Hemiptera and family Aleyrodidae) is a sap feeder. The adults are about 4-5mm long with...
Red spider mite
Red spider mite description Red spider mite, of the genus Tetranychus urticae, are sap feeders. Although there are several species of spider mites which attack...
Leaf hopper
Leaf hopper description Leaf hoppers are usually less then 13mm in length, with long slender tapered bodies. They tend to be pale green to tan...
Leaf miner
Leaf miner description The adult leaf miner (Liriomyza sativae) is a 1-1.8mm long shiny black fly with a prominent yellow triangle between the bases of...
Downy mildew on lettuce
Downy mildew is a serious problem in greenhouses especially under cold humid conditions. It is caused by the casual organism Bremia lactucae. Of the commercial...
Sclerotinia or watery soft rot
Sclerotinia symptoms Leaves, especially the older ones, start to wilt during any stage of growth. The wilting continuous until the plant collapses completely. The...
