The black gnats settled on the back side of leaves and on the stems of tomatoes. It is actively propagated and sucking out plant juices. After destroying the plant, black Midge moved to a nearby Bush and so until then, until you killed all the bushes of tomatoes. If no action is taken, the black gnat can for two weeks to destroy the tomato plant and Rob you of all of the crop.
Is there a good way to prevent black gnats, but this must be done before she came - to plant tomatoes in the garden should be so that they alternated with crops, of which black flies do not like. Aphids are deterred onion, garlic, herbs, and calendula.
There are several ways to deal with the black Midge. The first is OK if you caught the appearance of midges in the beginning and not much else. Can remove them from plants by hand or flush with water.
If clusters of midges is quite extensive, every leaf and stem manually process impossible. Will have to resort to folk or chemical compositions for spraying bushes. Soft gentle formulations can be prepared independently, using what is at hand in every home.
For example, this recipe: 2 tablespoons liquid soap mixed with two cups water and one Cup of vegetable oil. Instead of liquid soap you can use a commercial, grated on a grater and diluted with water. This group of plants should be sprayed twice a day, early in the morning and in the evening when pollinating insects do not fly.
Another remedy is garlic-based. Half a litre of water does a teaspoon of liquid (or grated household soap, two teaspoons of vegetable oil and five teeth of garlic. Crushed garlic is added to other components. The solution was infused for an hour, filtered through cheesecloth. The plants are sprayed once per evening after sunset.
Very effective is the remedy made from the leaves of tomatoes. You need two cups of chopped tomato leaves healthy to pour two cups of water and leave for 12 hours. Then a solution to treat the affected a black Midge bushes several times a day.
If tomatoes, black midges, and a lot of it multiplies rapidly have to deal with it by chemical means. You can buy them in the store and apply according to instructions. It is better to choose soft organic pesticides and insecticides. The most harmless to plants are the agents based on fatty acids or pietrino and vegetable oils.