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 along the sides. It typically moves by arching the middle part of its body upward. The adult moth is active at night (about 1 ½ [...]
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) that have prominent rows of dark bumps on their backs. Mature worm's colour varies from dark grey to light brown and have lengthwise stripes on [...]
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 circular pits each 3-9mm in diameter and up to 1 mm deep appear. They can coalesce to form large irregular sunken areas. The minimum temperature [...]
Selecting a cucumber pruning system The question arises which system should be used. Each system has its advantages and disadvantages according to the ability and managerial skill of the grower, the experience of his labour, capital available to build the various structures, climatic conditions of the area etc. The easiest [...]
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 a pale yellow body. The sweet potato whitefly can easily be identified by their red compound eyes. When feeding their wings are slightly apart creating [...]
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 plants, the red spider mite and the two-spotted spider mite are the most common. The red spider mite is often referred to as the “red [...]
Green bean fertigation must be controlled carefully since they are extremely fast growing. There are pro's and con's of fast growing crops. An advantage can be that any deficiency or toxicity can be outgrown quickly. The disadvantage is that the crop can develop one of these physiological disorders very quickly. [...]
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 in colour, and may have dark markings. They usually infest the lower surface of leaves and if disturbed move sideways very quickly. They also have [...]
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 the wings; the underside and the face between the eyes are yellow. Liriomyza trifolii differs in having the thorax covered with overlapping bristles that give [...]
