Guava soft scale

Guava soft scale (Pulvinaria psidii) is a significant agricultural pest belonging to the family Coccidae (order Hemiptera). Known as a species of soft scale insect, it is notorious for colonizing a wide range of fruit-bearing and ornamental plants, particularly in tropical and subtropical climates, as well as in greenhouses worldwide.

This insect is highly polyphagous, meaning it can infest a large variety of hosts. Key crops affected include guava, citrus, coffee, mango, gardenia, and various species of Ficus. In indoor gardening and nursery settings, it can become a persistent problem that is difficult to eradicate without sustained intervention.

The life cycle involves egg, nymph (crawler), and adult stages. A distinctive biological characteristic is the white, cottony egg sac (ovisac) produced by the adult female. After hatching, the tiny crawlers move to suitable feeding sites on the foliage or stems, where they attach themselves and begin feeding on plant sap.

The primary damage caused by Pulvinaria psidii includes severe sap depletion, which results in leaf yellowing, stunting, and premature drop. Additionally, the insects excrete honeydew, a sticky substance that promotes the growth of sooty mold. This mold covers the leaves, hindering photosynthesis and severely impacting the plant's overall vitality.

Effective management requires a multi-faceted approach. Chemical control involves the use of systemic insecticides or contact sprays during the crawler stage, which is the most vulnerable period. Furthermore, cultural practices such as pruning infected branches and maintaining proper sanitation are critical to preventing the spread of the infestation within a planting area.

• Regular inspection of the undersides of leaves and leaf axils.
• Application of horticultural oils to smother the insects.
• Introduction of natural enemies like parasitic wasps or ladybird beetles.
• Use of systemic insecticide drenches for long-term protection.