Pest control is very important to the successful gardener! Cultural practices, such as eliminating all weeds and grass from your garden, including the outside edges, are very important. This will minimize pests and diseases’ opportunity to migrate in from other places.
Also, maintaining dry wide aisles will reduce their opportunities for spreading.
And growing healthy, vigorous plants will reduce pests’ effectiveness perhaps more than anything else. This is one of the great benefits of The Mittleider Method, since plants are rarely in the ground long enough for pest populations to become a serious problem.
In order to learn the various types of bugs, and be able to distinguish which are harmful and how to attack them, I recommend you study chapter 20 in The Mittleider Gardening Course bookor Lecture #22 in the Video Lecture Series, for specific information.
Also, there is good information available on the internet. Two articles I particularly like are one by the University of Florida at http://ipm.ifas.ufl.edu, and one by Oklahoma State U at http://osufacts.okstate.edu/docushare/dsweb/Get/Document-2786/HLA-6434web.pdf
Diseases – Prevention and Control
Food For Everyone, a college-level textbook by Dr. Jacob R. Mittleider, has important chapters on both pest and disease control. For the serious grower this book is highly recommended.
As with controlling pests in the garden, we recommend that your first line of defense against disease is the use of several important preventive “cultural practices” that include:
1) Maintaining a totally weed-free garden with wide, dry aisles,
2) Pruning leaves off the ground,
3) Watering only at the soil level (never sprinkle) and only in the actual root area,
4) Growing seedlings in a protected environment and transplanting stocky, healthy seedlings into the garden,
5) Feeding plants a complete, balanced natural mineral nutrient mix that encourages healthy, rapid growth,
6) Harvesting when crops are mature, and
7) If using row covers or “mini greenhouses,” open the ends on cool days (50+), and set the covers to one side on warm days (65+), to maximize sunlight and circulation, and reduce excess humidity build-up.
By following these procedures your problems with pests and disease will normally be rare.
You may have been doing all of these things, and only the increased humidity and warmth of the row covers could give disease an opening.
If you are experiencing Downy Mildew, a fungus disease, general symptoms for all affected vegetable crops, which usually happen under high-humidity conditions, include spots appearing on leaves and a downy white or grey mold developing in these spots or on the undersides of the leaves opposite these spots.
With broccoli, cauliflower, cabbage, and Brussels sprouts, dark spots may develop on the heads as well as the leaves. Black streaks may be visible on stems and a white fuzzy growth may develop. Seedlings are especially affected.
The best solutions are preventative, and constitute physical controls, such as I have described above.
Also, it’s important to remove and burn all old leaves.
If you have the problem, if it is not too widespread, I recommend you remove all affected leaves immediately and improve the physical conditions as much as possible.
Biological control is your last option, short
of removing the entire crop.
“Wettable sulfur, sprayed on tomatoes every two weeks at a rate of 2 tablespoons per gallon will absolutely prevent mildew. And….it is cheap.
“One tablespoon of wettable sulfur to one gallon of water sprayed on squash leaves AFTER you have removed all infected leaves will control mildew on your squash.
“Preventive spraying is the best way to control mildew and only spray in the evening when the leaves of your plants have had a chance to cool down. Spraying on hot leaves will burn them. Ditto with tomatoes.
“Cucumbers are a problem and they do not like sulfur. Skim milk seems to do well on cukes.
“Keeping all leaves that do not look perfect removed daily from your plants, tomatoes, cukes, and squash, goes a long way in preventing the spread of the mildew. Mildew, after all, is a fungus and spreads via spores that blow in the wind.” Contributed by a Mittleider Gardening Group Member – Joanne “pathaj” from Southern California.
Several chemicals are sold to control downy mildew, including Benomyl, Copper, Folpet, Lime Sulfur, Sulfur and chlorothalonil. Counsel with the store from which you obtain any of these materials, and always, when using pesticides, read the entire label on the container and follow the directions. Because mildew will built up a resistance to fungicides over time, especially Benomyl, if the problem persists you will need to consider changing the materials used occasionally.