Plant Health
Preventative Pest & Disease Control
Article By: Monrovia - Horticultural Craftsman
Plants have an immune system just like we do. The healthier the plant, the more powerful its immune system is to fight off pests and disease. When plants are stressed due to heat, drought, poor soil or the wrong exposure, they grow weaker, and problems set in. The two most important things you can do are to keep your plants healthy, and frequently inspect them for early warning signs.
Don't Assume... Identify
No two years are ever the same in gardens. This is due to variation in the weather, with some years warmer or cooler, wetter or drier. When conditions are right for a particular pest or disease, it will flourish, but if things change the next year, you may never see it at all. However, there may be persistent problems due to susceptibility of a certain plant variety or something unique to your yard. Plants contain special chemicals that make them distasteful to bugs. When they are weakened y stress, the chemical levels are reduced and the plants becomes vulnerable. Often bugs attack the smallest, spindly plant of a group and will never spread to the healthy ones because their chemicals are more concentrated. These chemicals are so effective they are extracted for botanical pesticide such as pyrethrum, which is derived from a species of chrysanthemum.
For every pest in nature there is a predator bug that will leave the plant alone while dining on the bad bugs. These are collectively called beneficial and include ladybugs, praying mantis and lacewings. Protecting beneficial takes advantage of nature's control mechanisms. Chemical pesticides kill both pest population explosions once the predators are gone. The new approach to pest control is through least toxic measures designed to protect beneficial while controlling pests.
Assessing the Degree of Damage
Identification of pests is your key to control. It also tells you what kind of damage potential they represent. For example, a gang of aphids can distort leaves, but they are nothing compared to a gang of army worms that can defoliate a shrub overnight!
These three are the most common bugs found in gardens:
- Aphids are sucking insects that cluster on new growth.
- Spider mites are microscopic and dwell on the back side of the leaf.
- Caterpillars are voracious larvae that are very dangerous to all plants.
It's far easier to wipe out a few bugs when they first appear than to control an infestation later. Frequent inspection of your plants means that you'll catch problems early. Once the pest is identified, then you can choose one of these least toxic controls:
- Discourage small mites or aphids by knocking them off with a strong jet of water.
- Buy and release beneficial bugs and worms off your plants.
- Hand pock larger bugs and worms off your plant.
- Spray the plants with insecticidal soap for insects.
- Spray the plants with BT or other biological controls.
A Fungus Among Us
Most plant diseases are fungi that thrive under certain weather conditions. They most often attack roses but other trees and shrubs can be afflicted as well. It may be a temporary weather related condition or due to plants receiving too much shade.
Mildew is actually a group of white or gray powdery fungi that attack plants where moisture lingers on the leaves to pucker and distorts new growth. Mildews is more prevalent in damp climates, but occurs in dry ones as well. Mildew is common on Crape Myrtle trees and Roses, but can afflict just about every other. Removing affected leaves and racking up fallen ones is essential to control.
A variety of fungicides are used to control mildew and blackspot but they can be tenacious problem. Often the best solution is to move the plant to a location where it receives drying morning sun early in the day. The other alternative is to replace the plant with another variety with greater resistance.
Green Tip
Controlling damaging caterpillars is easy using nontoxic BT, or Bacillus thuringiensis. Simply apply it to plats in either powder or liquid form and once eaten by a caterpillar, the pest dies. BT is safe around both children and pets.
Healthier Plants... Naturally
Monrovia plants are naturally more resistant to pests and disease. Our soil mix contains mycorrhizal microorganism that live with roots to help plants resist debilitating problems. This benefit combined with care and attention makes out plants perform, and your garden remains as pest and disease free as possible.