Spider mites damage weed plants grown indoors or outdoors. They are pests which thrive in hot conditions, so they can be particularly destructive to weed plants grown under glass.
When a colony of spider mites gathers on the underside of leaves, they make holes in the protective layer to feed on plant fluids. If home remedies are not used to protect the weed plants, their leaves will lose moisture through holes made by spider mites and this will ultimately cause the leaves to turn brown and become dry.
7 Effective Home Remedies to Get Rid of Spider Mites
Home remedies are necessary to get rid of them, because mites can easily become resistant to the chemicals in insecticides or the chemical will also kill off the insects that prey on these pests. Some commercial pesticides will even result in a faster breeding cycle in spider mites, because of the increased amount of nitrogen that is added to the leaves.
1. Regular Hosing with Water
Pressure hosing with water will remove mite eggs from the underside of leaves, and should dislodge any adult mites. Care should be taken not to damage weed plants with high water pressure, but the water stream does has to be powerful enough to blast off the pests and reduce their numbers.
Hosing with water should take place at least once a week to prevent further infestation or to slow it down. The focus of pressure hosing should be on the underside of leaves and the lowest part of the plants.
Spider mites do not congregate on the upper surface of leaves and are not usually found near to the top of weed plants, so hosing down the lower parts is more effective.
2. Introduce Natural Predators
By increasing the number of insects that naturally prey on spider mites, their number will rapidly reduce and they can disappear completely. The most effective predator insects are lacewings, ladybugs and other mite species that are the natural predators of the spider mite.
Predator species can be purchased commercially and then released into the area where weed plants are grown. Phytoseiulus persimilis is a voracious killer mite that originates in Chile and it is now widely used in for biological control of the red spider mite. When they are released they will feed on all the spider mites they can find.
Ladybugs are also fond of feeding on spider mites and can consume a large number of them within a couple of weeks. They can be considered to be one of the best home remedies for getting rid of spider mites by being encouraged or introduced into a greenhouse or outdoors area where weed plants grow.
Conditions must be kept favorable for the introduced species to thrive, so that they will continue devouring the pests. The natural predators of spider mites will only be able to thrive if dusty conditions are avoided by regular spraying with water. Obviously no chemical insecticide should ever be used after a predator species has been released.
The best time to release predator species is during the winter, because it is easier to get rid of spider mites if they can be controlled in the months before the start of the breeding season.
3. Increase the Humidity
Spider mites dislike dry conditions and in an effort to gain more moisture they will do more damage to weed plants growing in dry or dusty conditions. Spraying and maintaining high humidity around the weed plants will help to reduce the risk of infestation, although it may not be enough to entirely eliminate the pests.
Before the breeding season for spider mites begins in the spring, all dry plant debris should be removed, along with old canes, dried out dirt and anything else that has become dry or dusty.
4. Use Homemade Rosemary Oil Spray
One of the best home remedies to get rid of spider mites is to make a natural insecticide spray from a 2% solution of essential oil of rosemary in water. Another way is to soak freshly cut rosemary sprigs in water for a few days, kept in warm conditions, and then to strain the liquid before bottling.
Homemade rosemary insecticide should be applied through a spray bottle, and aimed at the underside of leaves. It is a very effective method for getting rid of spider mites and will not destroy their natural predators.
Avoid using rosemary oil spray in a high temperature and never use it on any weed plants that are dehydrated. This is because spraying in hot and dry conditions can result in leaf burn.
5. Use a Dishwashing Soap Spray
An effective homemade insect repellent can be made from three tablespoons of dishwashing soap mixed with a gallon of water. Place this solution in a spray bottle, taking care to spray it onto the undersides of leaves. This treatment should be repeated every six days until all signs of infestation have disappeared.
There is a slight chance of leaf burning from the soap, so it is a good idea to test this spray first on one or two leaves of a plant first, before giving it a full spray.
6. Repeat Treatments to Stop Infestation
Repeat treatments are essential to be sure of killing off all generations of emerging spider mites. Their life cycle can be as short as seven to ten days in the summer, and they start to lay eggs when they are just one week old.
This means that killing off adults with one treatment is never enough to stop an infestation of spider mites. Whatever treatment is being used to get rid of them, it should be repeated every week until there is no longer any sign of new generations emerging to feed on the leaves.
7. Protect Weed Plants from Infestation
The best way to keep weed plants free from spider mites is by regular monitoring to look for signs of infestation and to make sure that growing conditions are not attractive to these pests. This means that weed plants should not be overcrowded and should be kept in moist conditions at a temperature that is not too high.
When infestation is seen to be affecting the leaves on any plant, those leaves should be pruned as soon as possible. It might be necessary to prune the plant heavily or even to pull it up if it has been badly affected.
Affected parts should be disposed of immediately in closed plastic bags and placed in the trash. This will prevent spider plants pests from transferring to other weed plants in the same environment.