Whether dealing with avocado plant thrips, onion plant thrips or thrips that target perennial and ornamental flowers, there are a number of different ways to prevent a serious infestation. Beyond a few common sense general rules such as avoiding excessive use of nitrogen fertilizer, making sure weeds on the perimeter of a garden are removed, and quickly removing old or spent flowers.

Pruning

It may sound simplistic, but pruning away damaged or destroyed portions of contaminated plants is an effective way to prevent thrips. In the case of avocado thrip control, changing the type and frequency of fertilizer along with pruning can be especially effective.

Thrips will scar avocado fruit if they feed off the harvest. However, if thrips nestle only on a plant's leaves, the damage is far less extensive. Again, with avocado plants, one preventative strategy involves pruning earlier in the growth cycle than normal. Rather than waiting to prune February through April, gardeners can do so in January, leading to more growth in May-June and thus more foliage to keep thrips distracted and away from the fruit.

Coverings, Reflective Mulch

Other ways to prevent thrips include covering the rows of plants with a fine mesh, vented polyethlylene, woven plastic, and other materials. The only downside of this approach is that a drip or irrigation watering system will be required to properly get water to the plants. The coverings can be removed once the plants get larger and temperatures begin to warm up.

Because many species of thrips are thrown off by ultraviolet light, some growers also like to surround that base of their plants with reflective mulch. The idea is that the light waves that bounce off the mulch and into the air make it hard or even impossible for thrips to find their plant prey.

Pesticides

Depending on the type of plants being targeted, pesticide products are of course also an option, especially when it comes to perennial or ornamental flowers. For example, in the case of western flower thrips, effective chemical control products include Guithio, Thiodan, and Carzol SP.