Diseases of crops grown and closed hydroponic systems can be a problem and occasionally catastrophic. However, the presence of a pathogen does not necessarily mean that a disease outbreak will occur. Although not fully understood, there are fine balances in hydroponic systems involving climate conditions, biological control agents, etc. that can keep pathogens in check. [...]
Everyone has become more knowledgeable about the spread of viruses and the diseases they cause. Just like the COVID virus, we have to understand the life cycle of each virus that cause diseases in greenhouse crops. Effective virus disease control requires controlling or shutting down three important links; the source of the virus, the vector [...]
Well planned spray programs are more effective than unplanned, random chemical applications. Have you ever considered spraying when there is no pests or diseases? Poorly planned spray programs or not following a spray program has the same effect. It costs a lot of money with no advantage other than the chemical supplier. Even nature loses, [...]
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 disease development is between 24-27°C (75.2 - 80.6°F)Bradbury, J.F. 1967. Pseudomonas lachrymans. Description of Pathogenic Fungi and Bacteria, No 124. Commonwealth Mycological Institute, Kew, England. It is caused by Pseudomonas syringae pv. lachrymans [...]
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 that are effective to control pests and diseases. This causes a high intensity selection pressure with limited products with the result that evolution is set in overdrive mode. Traits resistant [...]
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 crops, lettuce is most affected, but is also prominent with Endive, Escarole, Chicory, Salsify and Globe Artichoke. The fungus grows very fast and when the symptoms appear on the leaves, [...]
[/su_collumn] Sclerotinia infects crops such as lettuce, escarole and endives. Tomato fruit are seldom affected. It manifests itself as a damping-off when planted, wilting symptoms also referred to as “drop”. When fruit or leafy crops are transferred and infected by Sclerotinia, it is called as “watery soft rot”. The disease is serious during [...]
Grey mould is found on lettuce, escarole, endive and globe artichoke. The disease is most important during transit of these crops. The disease is caused by Botrytis cinerea Fr. Grey mould contributes to damping-off, especially in lettuce seedlings. Grey mould symptoms The symptoms are typical of those of damping-off. The fungus is usually identified by [...]
Septoria leaf spot is one of the most destructive diseases on tomato and is caused by Septoria lycopersici. It is most destructive during moderate temperatures and high rainfall. The disease destroys so much of the leaves that the plants fail to mature their fruits properly. Symptoms of Septoria leaf spot The disease occurs at any stage [...]
