Irrigation cannot compare with rainfall when it comes to making plants grow.
However, even with the good things, like rain, there can be problems. More rain equals more disease on plants, and these sporadic rains tend to cause disease problems to explode.
Most disease problems are caused by fungi or bacteria, and both are usually encouraged by warm, moist conditions. Hot + water (rain) = disease.
Therefore, under these weather conditions, diseases can develop and spread rapidly. So, keep an eye out for leaf-spots and fruit rots on fruits and vegetables, then treat with a fungicide if needed.
Most fungicides are protectants and don’t really cure diseases. They just keep diseases from spreading. So, spraying at the first signs of a disease is best, but some diseases are so devastating, preventative sprays are a must. Therefore, spray to prevent downy and powdery mildew on cucurbits, early blight and bacterial spot on tomatoes, and downy mildew on brassicas.
Diseases are very difficult to control. A simple mistake in diagnosis, selection of product and application can result in poor or no control.
First, properly diagnose your problem. You need to know your enemy before any war. If you are not a plant pathologist, ask questions.
A knowledgeable sales staff is an excellent reason to pick a farm center. Contact me. My office phone number is 843-519-2402. I hate plant problems, but as one vegetable farmer noted, “Without plant problems, they would not need me around – I guess job security.”
In my 29 years of being a county agent, I have become very good at pointing out plant problems and hopefully as good at providing solutions. Also, you can bring a sample of your problem to our office for diagnosis, and if I cannot answer, it will only cost you $20 to send to our Plant and Pest Diagnosis Clinic. Bring as large of a sample as possible.
Next, get the right product to control your problem. Manufacturers produce and package many different types of fungicides, but you are limited by what the local garden stores have in stock. Many times, the same fungicide will be sold under many different brand names.
Also, one fungicide might do an excellent job in controlling one disease, but it might perform poorly in controlling another disease.
Always read and follow the product label. The label is the LAW. It might be long and complicated, but it will contain all types of useful information, such as diseases controlled, rates and how to apply the product.
Finally, and most importantly, apply the product properly. Always apply sprays in late evenings when it is not going to rain and bees have left the area.
In the heat of the day, even water can cause burn on plants. Most fungicides need to be applied on the top and bottom of all leaves. Thorough coverage is essential for control. High spray pressure with hollow-cone nozzles is the best. Again, read and follow the label.