Best Pesticide For Whiteflies

Whiteflies can be a major problem for any plants people want to grow particularly indoors. They are very small, flying insects that are attracted to the color yellow, leaving blotchy marks on your leaves. Since they love the color yellow, they will attack anything yellow first. Whiteflies are tiny but dangerous insects which can infest our plants, with then being stingy not only to the plants but us too. They sap out vital nutrients from the leaves and inject toxins into the roots. It’s important to have control over this pest in order to have a healthy and flourishing home garden.

Best Pesticide For Whiteflies

A certain number of whiteflies may be tolerated when they do not cause significant damage. This tolerance level varies according to the host plant and individual preferences. A few adults feeding on plants will usually not cause significant damage and do not warrant treatment. However, if monitoring reveals an increasing number of eggs and nymphs on young leaves and the weather conditions are favorable, intervention may be required to prevent future damage.

Intervention may be physical/mechanical control, biological control or chemical control. Physical/ mechanical control includes removing heavily infested leaves or plants and using a high-pressure water spray on the underside of leaves. Removing infested leaves from plants may be enough to control small populations on less preferred hosts. Removing a few infested plants early may prevent future problems. High-pressure water sprays will wash away honeydew and sooty mold accumulations and reduce populations of adults and nymphs. High-pressure water sprays are recommended at least once a week for three consecutive weeks and can be repeated as necessary.

Biological Control

Biological control is the manipulation of natural enemies to prevent or suppress damage from pests. Several species of predators and parasitoids are natural enemies of whiteflies. Predators of whiteflies include ladybeetles (Delphastus and Nephaspis), green lacewings (Chrysopa and Chrysoperla), minute pirate bugs (Orius), big eyed bugs (Geocoris) and damsel bugs (Nabis). Parasitoids (insect parasites) of whiteflies include minute wasps (Encarsia and Eretmocerus) about 1 millimeter long and either yellow, dark brown or bicolor (brown head and yellow body), depending on the species. Females of these tiny, parasitic wasps lay their eggs inside whitefly nymphs. When the wasp eggs hatch, the larvae feed internally on the whitefly nymphs, eventually killing them.

In addition to predators and parasitoids, whiteflies are naturally attacked by insect pathogens. Spores from the fungal pathogen Beauveria bassiana, which causes white-muscardine disease in insects, have been formulated into insecticidal products (see Table 1).

Biological control can be achieved by importing and releasing natural enemies from areas where pests originate, by purchasing and releasing commercially available natural enemies or by conserving naturally occurring ones. Importing natural enemies—also known as classical biological control—involves coordinated efforts of university, state and federal scientists and regulators. Classical biological control programs have been conducted against several whitefly species including silverleaf whitefly, citrus whitefly, citrus blackfly and giant whitefly.

The purchase and release of natural enemies is also known as augmentation biological control. Augmentation biological control has been effective in controlling whiteflies in greenhouse ornamental production. A list of commercial suppliers of natural enemies in North America can be obtained by visiting www. cdpr.ca.gov/docs/ipminov/bensupp.htm.

Delphastus pusillus is the most whitefly-specific predator available. It feeds primarily on whitefly eggs but may also consume nymphs. It is particularly useful in reducing whitefly populations in greenhouses, although it may also be used outside. Recommended release rates are seven to ten per m2 (10 ft.2).

Eretmocerus eremicus is the most effective parasitoid available for biological control of silverleaf whitefly, while Encarsia formosa is effective for treating the greenhouse whitefly. Parasitoids are effective at suppressing low whitefly population densities and may prevent a pest outbreak but do not control an existing one. Recommended release rates in the greenhouse vary with whitefly population density from three wasps per 2 m2 ( 2 per 15 ft.2) every 1-2 weeks, starting at first sign of whitefly presence, to three or more weekly introductions of three to nine wasps per m2 (10 ft.2) when whitefly populations are initially established, to weekly releases of one to three wasps per plant for highly susceptible crops like poinsettia.

The easiest biological control method in a landscape is to conserve naturally occurring predators and parasitoids. Conservation biological control involves the careful selection and use of pesticides only when necessary to prevent pest damage. Judicious use of insecticides not only will preserve natural enemies but will also reduce health and environmental risks.

Chemical Control

Several classes of insecticides are labeled for use against whiteflies on ornamental plants. Table 1 lists some whitefly control products available to commercial ornamental producers, and Table 2 shows products available to homeowners. Insecticidal soaps and horticultural oils are contact insecticides that cause suffocation and desiccation of nymphs and adults. Soaps and oils are among the best alternatives for whitefly control by home owners because they are effective, preserve natural enemies and are relatively safe. It is important to thoroughly cover the underside of leaves and repeat applications. Insect growth regulators, when applied during the immature stages, prevent adult whitefly development. These products generally do not kill adult whiteflies present at the time of a treatment.

To reduce the impact of insecticides on natural enemies, avoid the frequent use of broad-spectrum insecticides (those labeled against many pests) because these also kill predators and parasitoids. Avoid frequent, long-term use of insecticides with the same mode of action because this may lead to the growth of populations of insects that are resistant to the chemicals. Insects that are resistant to one insecticide may also be resistant to other insecticides (cross-resistance).

Under certain temperature, humidity, water and shade conditions, pesticides may also cause injury to certain plants (phytotoxicity). Generally, apply pesticides during early morning or late afternoon to avoid the hottest part of the day. Water plants 1-2 days before applying pesticide. Always check the product label for the list of plants that may be injured by the pesticide.

List of Best Pesticide For Whiteflies