Citrus Mealybug Performance and Plant Strata Preference on Different Coffee Varieties

Area of Science:

• Plant-insect interactions
• Chemical ecology
• Agricultural entomology

Background:

• Optimal defense theory suggests plants protect young tissues, influencing herbivore distribution.
• Citrus mealybug (Planococcus citri) is a significant coffee pest.
• Understanding pest preference is crucial for integrated pest management.

Purpose of the Study:

• To investigate the feeding and oviposition preferences of citrus mealybugs on different coffee plant parts.
• To assess the impact of these preferences on mealybug life history and fertility.
• To compare preferences and performance between Coffea arabica and Coffea canephora varieties.

Main Methods:

• Evaluated feeding and oviposition site selection of P. citri on apical, median, basal, and trunk regions of C. arabica and C. canephora.
• Measured life history parameters (net reproduction rate, intrinsic rate of increase, generation time) for P. citri on both coffee varieties.
• Analyzed spatial distribution of different P. citri developmental stages.

Main Results:

• P. citri showed a strong preference for young (apical) leaves for feeding and oviposition, overriding plant defense compounds.
• Over 55% of mealybugs preferred apical leaves on C. canephora, compared to over 38% on C. arabica.
• Mealybug population growth rates (R0, rm) were significantly higher on C. canephora, with population doubling in 15 generations compared to C. arabica.

Conclusions:

• Citrus mealybugs actively select nutrient-rich young tissues, demonstrating host plant preference for C. canephora.
• Host plant variety significantly impacts mealybug fitness and population dynamics.
• Understanding mealybug dispersion and site selection is key to managing coffee infestations.