Integrated Pest Management (IPM) for Icerya seychellarum

Integrated Pest Management (IPM) for Icerya seychellarum

 Overview:

Icerya seychellarum, commonly known as the Seychelles scale, silvery cushion scale, breadfruit mealybug, iceplant scale, or Westwood scale, is a sap-feeding insect that poses a significant agricultural threat. It feeds on phloem from a wide range of host plants, causing damage through sap depletion and honeydew secretion. Ants have a mutualistic relationship with I. seychellarum, feeding on its honeydew and offering protection from natural enemies. Icerya seychellarum was first detected in Region 7 on March 20, 2024 in Saint Lucia. The pest exhibits four annual generations with distinct activity peaks: a small peak in March, an intermediate peak in June, a third peak in August, and a final peak in mid-September. The economic threshold (ET) for initiating control measures is essential in managing infestations. When the ET reaches 27.24 pre-adults per leaf, implementing management strategies becomes necessary to prevent further economic damage.

Host Range:

The breadfruit mealybug affects over 60 plant species, including economically significant crops like breadfruit (Artocarpus altilis), mango (Mangifera indica), guava (Psidium guajava), citrus (Citrus spp.), soursop (Annona muricata), papaya (Carica papaya), coconut (Cocos nucifera), avocado (Persea americana), fig (Ficus spp.), coffee (Coffea spp.), cashew (Anacardium occidentale), banana (Musa spp.), sugar apple (Annona squamosa), and pigeon pea (Cajanus cajan).

 Biology 

The insect is oval-shaped, measuring 6–9 mm in length. Adult females are yellow to brick red, coated in a white wax with silky hair tufts along the edges. These hermaphroditic females lay approximately 33 light orange eggs in rows within silken ovisacs. Offspring develop through unfertilized eggs, passing through incomplete metamorphosis (egg, nymph, adult).

 Symptoms of Infestation 

The breadfruit mealybug typically infests leaves, stems, twigs, and fruit, especially on the undersides of leaves near the veins. Feeding on phloem results in honeydew production, which supports sooty mold growth. This mold interferes with photosynthesis and respiration, reducing plant vigor and fruit quality. Severe infestations lead to yellowing leaves and dieback of young shoots.

 Identification

Accurate identification of the Seychelles scale or Breadfruit mealy bug necessitates preparing specimens on a microscope slide and examining them under high magnification. Key diagnostic features include observing the presence of long, fine, silky hairs covering the body.

Detection 

Detection involves looking for the large mealybugs (up to 10 mm) along major leaf veins and stems, where they are often most visible.

 IPM Strategies for Control

Integrated Pest Management (IPM) for I. seychellarum includes the following approaches:

   – Monitoring and Identification: assess infestation levels.

   – Cultural Control: to reduce habitat suitability.

   – Biological Control: utilizing natural predators or pathogens.

   – Mechanical Control: through physical removal.

   – Chemical Control: where necessary and as a last resort.

   – Educational Outreach: to inform stakeholders about control measures.

   – Regulatory Measures: to prevent the spread.

 This comprehensive IPM approach will mitigates the impact of the Seychelles scale on diverse plant species in Saint Lucia, thereby safeguarding agricultural productivity, ecosystem health, and human well-being while simultaneously enhancing food security and promoting sustainable agricultural practices. To advance this IPM collaboration, the ongoing awareness campaign focuses on identifying the breadfruit mealybug pest and conducting an island-wide survey to assess its distribution and impact.