Aphids

The aphids Aphids are small, pear-shaped insects with a pair of horn-like projections along the dorsal side of their bodies. The main species that commonly attack cannabis are Myzus persicae, Aphis gossipii, and Macrosiphum euphorbiae.

Adult aphids can be winged or wingless, depending on the circumstances. Generally, populations on plants are wingless. Winged aphids appear in overpopulations and/or when it is necessary to change the host plant. Thanks to their ability to modify their morphology as needed, they adapt very well to changes in climatic and nutritional conditions.

Characteristics and damage caused by aphids

The size varies between 1-3 mm depending on the species. And its coloration usually includes shades such as green, yellow, pink and black.

Under favorable weather conditions, overpopulation occurs rapidly. At 25°C, it takes little more than a week for a nymph to become a live adult.

Aphids take refuge under cannabis leaves, on herbaceous stems, and on tender shoots, forming dense colonies. When disturbed, they may drop to the ground as a defense mechanism.

Damage is caused by both nymphs and adults. Their piercing-sucking mouthparts, with a long stylet, are capable of penetrating leaves and reaching the phloem vessels, where they extract sap. They are also capable of transmitting viruses between plants.

Affected cannabis plants typically exhibit leaves with localized chlorosis in the areas of the infestation. If the infection is severe, the chlorotic leaves may display white tinges due to a lack of pigments and reddish tinges due to the accumulation of anthocyanins. Deformities may also appear in the newest cannabis leaves.

Although they typically affect the tenderest aerial parts of plants, such as shoots and leaves, attacks have been recorded on the roots of cannabis plants grown in hydroponic systems. These insects entered the plants through infected plant material.

Its appearance outdoors is natural in spring and summer.

Severity of aphid infestation:

Aphid Video

CONTROL METHOD

Preventing these insects outdoors is complex; aphid colonies appear spontaneously during hot weather.

Promoting biodiversity and beneficial insects is the practice that will significantly reduce the incidence of aphid infestations. The spontaneous appearance of natural enemies, alongside aphid colonies, is common. Therefore, the use of broad-spectrum insecticides should be avoided.

In indoor crops, the use of blue sticky traps, which attract winged individuals, is necessary to carry out the recognition, counting and study of the evolution.

Biological control using the parasitic wasp is well known Aphidus colemani. The use of ladybugs as species is also very good Armonia axyeridis, Adalia bicapunctata, Coccinella septempunctata and Adalia decempunctata. These insects are associated with aphid colonies and are very frequently found naturally in outdoor crops.

Temporary control using insecticides can be effective as long as several active ingredients are combined, since aphids tend to develop resistance quickly.