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How to recognize and combat weevils in fruit

Weevils

Insect

Type:

Risk to the plant:

HIGH

Different species

Pathogen:

How to recognize and combat weevils in fruit

Gorgojos

WHO CAUSES IT?

Weevils are insects belonging primarily to the family Curculionidae, although the term can encompass various species that attack different types of fruit. They are insects with chewing mouthparts and, in many species, a characteristic rostrum or extension of the head. Adults typically feed on plant tissues, leaves, shoots, flowers, or fruits, while the immature stages of many species develop inside plant tissues or the fruits themselves. The female lays her eggs near the fruit or directly on it, depending on the species. After hatching, the larvae begin feeding on the tissues and can penetrate the fruit, where they remain protected from many external treatments. During this stage, the larvae progressively consume the pulp and, in certain species, can reach the seeds or the interior of the reproductive organs. Upon completing their development, the larva may leave the fruit to pupate in the soil, in plant debris, or in other suitable shelters, although some species complete part or all of their transformation within the fruit itself. The adult then emerges and can move to new fruits and plants to feed and reproduce. The duration of the different stages depends considerably on the species and environmental conditions, especially temperature, food availability, and humidity. Under warm and favorable conditions, development can accelerate, and some species can complete more than one generation during a growing season. Adults can survive between seasons by taking refuge in the soil, plant debris, bark, crevices, and other sheltered places, from where they recolonize crops when conditions are favorable. The presence of damaged fruit, plant debris, and refuge areas can promote the persistence of populations. Adult dispersal between plants occurs mainly through direct movement, while the transport of infested fruit can contribute to the introduction of certain species into new growing areas.

SYMPTOMS

Weevils can cause both direct and indirect damage to fruit. Adults may make small bites or perforations while feeding, and females may lay eggs on or near the fruit. Subsequently, the larvae of certain species penetrate the fruit and feed on the pulp, seeds, or other tissues, creating galleries and progressively destroying the internal structures. Affected fruit may exhibit entry holes, small perforations, sunken areas, soft tissue, deformities, and a loss of commercial quality. When infestation occurs in the early stages of development, the damage can cause premature fruit drop, while infestations near ripening can lead to significant losses during harvesting, transport, and storage. The wounds caused by the insects can also facilitate the entry of fungi and bacteria, increasing the likelihood of secondary rots. In some species, the presence of larvae inside the fruit may not be externally apparent until the damage is advanced, making detection and control difficult. Among the most common signs are:

• Small entry or exit holes on the fruit surface.

• Perforations and galleries produced by larvae inside the fruit.

• Feeding damage caused by adults on the fruit surface.

• Presence of larvae or larval remains inside the fruit.

• Deformed or irregularly growing fruit as a result of attacks during the early stages of development.

• Sunken, necrotic, or discolored areas around the points of attack.

• Softening and progressive deterioration of internal tissues.

• Damage to seeds or internal fruit structures when the species feeds on these parts.

• Premature fruit drop in severely affected fruit.

• Presence of excrement, feeding remains, or debris in the internal galleries. • Appearance of secondary rots favored by insect-caused wounds.

• Reduction in the weight, quality, shelf life, and commercial value of the fruit.

• Presence of externally healthy fruit containing larvae or internal damage.

• Increased damage during storage when the fruit was infested before harvesting.

Fruit weevils: How to recognize and effectively treat them

Fruit affected by weevils with holes and surface damage

Weevils: Symptoms, damage and solutions in fruit

DEVELOPMENT CONDITIONS

Temperature:

20-30 °C

Humidity:

60-90 %

HOW IS IT SPREAD?

Movement of adults, Flight of adults, Infested fruit, Infested plant material, Plant debris, Contaminated soil, Contaminated tools and equipment, Transport of fruit, Transport of plant material