The Cassava Mealybug (Phenacoccus manihoti) in Asia: First Records, Potential Distribution, and an Identification Key

Soroush Parsa,Amporn Winotai,Takumasa Kondo,Peter Shaw

doi:10.1371/journal.pone.0047675

Abstract

Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), one of the most serious pests of cassava worldwide, has recently reached Asia, raising significant concern over its potential spread throughout the region. To support management decisions, this article reports recent distribution records, and estimates the climatic suitability for its regional spread using a CLIMEX distribution model. The article also presents a taxonomic key that separates P. manihoti from all other mealybug species associated with the genus Manihot. Model predictions suggest P. manihoti imposes an important, yet differential, threat to cassava production in Asia. Predicted risk is most acute in the southern end of Karnataka in India, the eastern end of the Ninh Thuan province in Vietnam, and in most of West Timor in Indonesia. The model also suggests P. manihoti is likely to be limited by cold stress across Vietnam's northern regions and in the entire Guangxi province in China, and by high rainfall across the wet tropics in Indonesia and the Philippines. Predictions should be particularly important to guide management decisions for high risk areas where P. manihoti is absent (e.g., India), or where it has established but populations remain small and localized (e.g., South Vietnam). Results from this article should help decision-makers assess site-specific risk of invasion, and develop proportional prevention and surveillance programs for early detection and rapid response.

Highlights

The cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), is one of the most severe pests of cassava (Manihot esculenta) in the world [1]
The potential spread of P. manihoti into more Asian countries remains a prime concern for cassava production in the region [6]
In an effort to support decisions to manage this invasive pest, this article reports P. manihoti’s known invasive distribution, predicts its potential distribution in Asia, and presents a taxonomic key that distinguishes it from all other mealybug species associated with the genus Manihot

Summary

Introduction

The cassava mealybug, Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae), is one of the most severe pests of cassava (Manihot esculenta) in the world [1]. P. manihoti was not known to occur in Asia until 2008, when it was first detected in Thailand Since that year, it has spread aggressively throughout Thailand’s cassava-growing region [4], invading its neighboring countries and Indonesia [5] (Fig. 1), and raising significant concern over its potential arrival to more countries [6]. It has spread aggressively throughout Thailand’s cassava-growing region [4], invading its neighboring countries and Indonesia [5] (Fig. 1), and raising significant concern over its potential arrival to more countries [6] Responding to this concern, we present the first records of P. manihoti invading Asia and use them to estimate the climatic suitability for its establishment throughout the region. To further support detection and response efforts, we provide a taxonomic key that differentiates all mealybug species recorded from the genus Manihot

Methods

Results

Conclusion