New Records of Phenacoccus solenopsis Natural Enemies in Europe and Taxonomic Additions on Anagyrus matritensis

TL;DR

Researchers discovered new natural enemies of the cotton mealybug in Sicily, including a new parasitoid species to Europe and additional details on another parasitoid.

Contribution

The first European record of Aenasius arizonensis and new morphological details for Anagyrus matritensis associated with Phenacoccus solenopsis.

Findings

Aenasius arizonensis was reported for the first time in Europe.

Anagyrus matritensis was recorded for the first time in association with Phenacoccus solenopsis.

Generalist coccinellid predators were observed preying on the cotton mealybug.

Abstract

Phenacoccus solenopsis (Hemiptera: Pseudococcidae) is threatening protected horticultural and ornamental crops in Mediterranean countries, and research into indigenous natural enemies is needed as a sustainable biological control tool. Field surveys were carried out to discover the natural enemies attacking the cotton mealybug in Sicily (Italy) where the pest is currently present. Hymenopteran parasitoids and generalist coccinellid predators were reported. Aenasius arizonensis (Hymenoptera: Encyrtidae) was reported for the first time in Europe, and Anagyrus matritensis (Hymenoptera: Encyrtidae) was recorded for the first time in association with P. solenopsis. The two parasitoid species were identified by morphological features and molecular tools using a partial sequence of the COI mitochondrial gene. Further morphological details were also added to the original description for A. matritensis. The generalist predators Cryptolaemus montrouzieri, Hippodamia variegata and Parexochomus nigripennis (Coleoptera: Coccinellidae) were also recorded preying on the cotton mealybug.

The cotton mealybug Phenacoccus solenopsis (Hemiptera: Pseudococcidae) is a polyphagous invasive species native to America and considered one of the major cotton pests in Asia. It is currently threatening horticultural and ornamental protected crops in Mediterranean countries. Due to ecological and environmental concerns, the conventional chemical control of P. solenopsis in new areas of introduction is being replaced by exploring the potential of indigenous natural enemies as a sustainable biological control tool. After P. solenopsis introduction in Sicily (Italy), field surveys were conducted on native natural enemies attacking the mealybug to select promising biocontrol agents for field applications. For the first time, Aenasius arizonensis (Hymenoptera: Encyrtidae) was reported in Europe, and the native Anagyrus matritensis (Hymenoptera: Encyrtidae) was recorded in association with P. solenopsis. The two parasitoid species were identified by morphological features and molecularly using a portion of the mitochondrial cytochrome oxidase subunit I (mtCOI) gene. Because of missing information, additional morphological features were provided for the morphological identification of A. matritensis. In addition, the generalist predators Cryptolaemus montrouzieri, Hippodamia variegata and Parexochomus nigripennis (Coleoptera: Coccinellidae) were also recorded attacking the invasive mealybug.

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