Biological control and management of Dalbulus maidis (Hemiptera: Cicadellidae) with egg parasitoids: a review

The corn leafhopper Dalbulus maidis (DeLong & Wolcott) has become one of the most important pests on maize throughout the American continents. Nymphs and adults of D. maidis are efficient vectors of maize pathogens that produce corn stunt diseases. Biological control using predators, entomopathogenic fungi, and parasitoids against D. maidis nymphs and adults are reviewed, giving special attention to their effect on transmission biology. Egg parasitoids of the corn leafhopper are becoming the best alternative to control D. maidis populations. The present review identifies the most common and abundant egg parasitoids in maize fields throughout tropical America, characterizing them both morphologically and molecularly. These parasitoids are Anagrus virlai Triapitsyn (Hymenoptera: Mymaridae) and Paracentrobia subflava (Girault) (Hymenoptera: Trichogrammatidae). The development and behavior of these 2 species are also reviewed, and a new methodology is presented for attracting and releasing these parasitoids in maize fields. This new methodology is based on the conservation biological control strategy of edge management, combined with the augmentative biological control strategy of egg parasitoid release. The effect of diet on adult parasitoid fitness is also analyzed. Finally, the use of volatile organic compounds to improve the efficiency of these egg parasitoids in finding D. maidis eggs is reviewed. Further studies are suggested and gaps in knowledge are highlighted and analyzed throughout the review.