Whitefly

The whitefly, It is a small winged insect that has a piercing-sucking mouthpart and that in different phases of its cycle feeds on cellular contents of the cannabis plant.

It is considered one of the most important pests in crops worldwide, due to the serious infestations it produces and its difficult control by traditional methods.

Whiteflies excrete a sticky, sugary substance known as honeydew or molasses, which coats leaves and, in certain quantities, can clog stomata, thus reducing transpiration. This honeydew can also serve as food for other insects, such as ants, and for other microorganisms. fungus.

Whitefly spread and damage

In the species Trialeurodes vaporariorum The time that elapses from egg to adult can last about 20-25 days at about 30ºC and more than 30 days at 20ºC.

While in the spice Bemisia tabaci At 20ºC development can last about 60 days, at 25ºC about 30 days, while at 30ºC it is reduced to only 20 days.

The number of eggs ranges from a few dozen to hundreds under favorable temperature conditions.

In addition to temperature, the variety cultivated is also an influential factor in the spread of whiteflies.

Humidity has very little influence on the development of whitefly populations. In contrast, ambient temperature has a fundamental impact on all the insect's metabolic processes, both embryonic and post-embryonic.

These species have a mouthpart in the form of a very fine and long stylet, which allows them to reach the phloem ducts of the leaves and feed on the elaborated sap.

Feeding punctures are visible to the naked eye. Although circular, chlorotic spots may appear on the upper surface of cannabis leaves, these can indicate the presence of larvae on the underside. These small perforations damage the plant at a cellular level. When the infestation is severe, the leaves can lose their photosynthetic function, affecting yield.

Whiteflies are also known to be potential transmitters of various viral diseases that affect cannabis.

Severity of whitefly infestation:

Whitefly Video

Prevention and control of whitefly

Prevention is difficult outdoors due to continuous exposure. Maintaining beneficial insects and plant biodiversity outdoors will significantly reduce the incidence of whiteflies. Removing potentially host plants is also a good preventative measure.

In indoor growing, yellow sticky traps are useful for identification and counting, as is the use of insect screens over air inlets and outlets. The most common way for pests to enter indoors is through the introduction of infected plant material.

Since the typical climatic conditions of indoor crops are very favorable for its development, prevention will be crucial for its control.

Some insecticides, such as neem oil, can be quite effective as repellents, reducing the formation of harmful pest populations during the vegetative growth phase. It's important to remember that foliar application of water during the flowering phase is not recommended, as it increases the risk of fungal infections on the inflorescences.

Controlling a population with numerous adult individuals during the flowering phase is more complicated because the trichomes hinder the search and capture of parasites and predators. Prevention and the early release of natural enemies significantly reduce the risk of reaching critical whitefly populations, which can be highly damaging to plants.

Learning to live with whiteflies is the idea that outdoor growers must accept, but this does not mean they should ignore them, as otherwise production will be seriously affected.

biological control

The most frequently used commercial natural enemies are:

Predatory mites Amblyseius swirskii or the bedbug Macrolophus caliginosus Both species of whiteflies attack indiscriminately. Its effectiveness is excellent when the infestations are severe, especially during the flowering phase.