Try this website http://organiclifestyles.tamu.edu/ for more information on gardening organically. This is a TAMU educational website filled with lots of information.
This link helps identifying your plants problems.
THE DIRT DOCTOR'S BASIC ORGANIC PROGRAM.
Below is additional information you may find helpful.
Your garden center offers lots of safe, nontoxic products for use in repelling and eradicating insects, pests and disease that threaten your gardens. Barriers such as netting and row covers protect plants from flying insects as well as from deer and other hungry mammals. Copper tape can be used to protect trees and plants from slugs and snails. Bacillius thuringienses, or B.t., is a bacterium that kills leaf-eating caterpillars by invading their digestive system. B.t. is sold in both powder and liquid forms under a number of trade names including Dipel, Condor and Biotrol. Other bacterial controls available include Milky Spore Disease (Bacillus popillae) for use against Japanese Beetle grubs.
Releasing large numbers of Lady Bugs or Praying Mantis into areas of your garden infested with insect pests is lots of fun and can be a very effective means of controlling aphids, mealy bugs, leaf worms, and many other pests. Lady Bugs should be released at night near the base of infested plants where they will seek out and devour insect pests. Praying mantids are voracious predators that will feed on many of the larger insect pests including grubs, beetles, leafhoppers and caterpillars. These beneficial insects are available for sale at garden centers and through mail order.
Now that our vegetables and flowers are planted and thriving, it’s prime time for the hoards of insect pests and diseases to invade our little piece of paradise. Here are a few tips to help you through this scary attack.
Protect your garden plants from cabbageworms, caterpillars, hornworms, aphids, flea beetles and other chewing/sucking insects by routinely using a natural spray that you can make at home. The spray must be applied regularly, especially after a rainfall. Brew up a batch as follows:
6 cloves of garlic
Blend & let sit for 1 - 2 days. Strain & use as spray. Ground cayenne or red hot pepper can also be sprinkled on the leaves of plants (apply when leaves are slightly damp) to repel chewing insects or added to the planting hole with bone meal or fertilizer to keep squirrels, chipmunks, dogs and other mammals away from your gardens. Be sure to reapply after rain.
Here are some safe and easy steps you can take to reduce insect damage to your garden. To prevent cutworm attacks, place a newspaper or cardboard collar around the stems of tender transplants at the soil surface. Crop rotation and good garden sanitation is essential to repelling squash bugs and cucumber beetles. Heavy mulching can help prevent potato and cucumber beetle larvae from finding the plants. Row covers are another effective barrier against insects, though they may need to be removed to allow pollination to occur. Interplanting crops with aromatic plants like garlic, chives, or marigolds can repel many problem insects. Soap and water, garlic, and hot pepper sprays can easily be prepared at home for use against many pesky garden insects. The best solution to pest problems, however, is maintaining sound garden practices like building healthy soil, rotating crops, and cleaning up your garden at the end of the season.
Powdery mildew is a fungal disease that affects beans, cucumbers, melons, peas, pumpkins, squash and strawberries as well as many fruit trees and roses. Black spot is a fungal disease that produces black spots on the leaves of infected roses. In severe cases, the plant can be defoliated. To remedy these problems, mix 3 Tbs Baking Soda, 2½ Tbs horticultural oil and one gallon of water. Spray the mix onto infected plants. Reapply as often as needed.