[ Home ] [ Up ] [ Program Details ] [ What We Grow ] [ Farm History ] [ Subscribers ] [ Chefs ] [ Research ] [ Q & A ] [ Links ]

Pest Management  
[ Planting ] [ Growing ] [ Pest Mangagement ] [ Harvesting ] [ Clean-up ]

            Pest management is a challenge in south Florida. Luckily, the development of many new, safer pesticides enables us to grow almost pest-free vegetables. With a few exceptions (and those are quickly disappearing from the market), the pesticides used today are not the same as those that  were used in the 50's-80's. Most of the older pesticides killed  living organisms by attacking them at several places in their metabolic and/or reproductive processes. This enabled them to kill or injure many different types of organisms, in addition to the target pests. These chemicals  were easy and cheap to use because one pesticide could often kill all the insects in a crop, and had enough residual effects to keep killing them for even several weeks.

            Many of the newer classes of chemicals are synthetic forms of naturally occurring pesticides, which generally break down quickly in the environment and often attack only one site in the organism. So, they  are usually specific for one or more closely related pest species and do not affect the beneficial organisms. While this is an advantage as far as safety and environmental effects, it can also mean that the pests are more likely to develop resistance. So, it is important to rotate them with others which have different “modes of action”. These new pesticides are also much more expensive than the older ones!

 Several times, we have purchased beneficial insects, but we find that we usually do better by encouraging the natural populations of “beneficials”.

   During most of the growing season we spray twice a week. However, the chemicals used in the spray mix vary a lot.  When possible, we use pesticides that would be allowed under organic rules, and we also use many of the newer synthetic ones. We scout the crops and, when possible, spray only for the problems we see. However, in the spring and fall, high temperatures and humidities increase fungal and bacterial diseases. Since most fungicides prevent, rather than cure, diseases, we must anticipate the disease problem in order to effectively control it. So, when conditions are right for development of diseases that are usually a problem, we spray with fungicides. On the other hand, in a cool, dry winter, we may not have to use fungicides for several weeks.

 There is always one or more species of caterpillars (popularly called “worms”) trying to eat our crops. They include fall armyworms, beet armyworms, cabbage worms, corn earworms, and diamondback moths. So, our spray mix always contains a worm control insecticide. Most of the time it is one of the forms of Bacillus thuringiensis, a biological worm control. Periodically, especially around a full moon (when the mama moths like to come out and lay their eggs), we alternate with a Spinosad (another biological) or an insect growth regulator which kills the worms by preventing them from continuing their life cycle.

  Periodically, spider mites, or broadmites may build up on some crops. Since they are related to spiders, rather than being insects, they require use of a miticide.

  Other insect pests are more of a problem because of the diseases they carry than because of the direct damage they do. Whiteflies are the worst for us-they carry viruses which limit the production of most of our squash crops and our spring tomatoes. In addition to the  silver reflective plastic which confuses flying insects, at planting time, we add a systemic insecticide with the starter fertilizer solution. This chemical, the same as the one that is used on pets for flea control, protects the transplants for about 6 weeks. 

Since we never have a winter, some kind of weeds grow all year round. Our plastic and compost mulches help to control them, and the summer cover crop smothers a lot of the summer weeds. But, during the growing season we have to spray or wipe the alleys between the crops with non-persistent herbicides, so that we can get through to harvest the crops. The crew also does a lot of hand-weeding.

In those times when a possible frost is predicted, we often  use row covers to protect crops. These fabrics are made especially for covering crops. They come in large rolls and can give 2-6 degrees of cold protection. Since it’s very difficult to put them over staked tomatoes, especially the tall stakes, we usually concentrate on the young crops. Most of the cool season crops can stand a light frost, although even the hardy ones can be damaged if temperatures drop quickly.