The Effect of Endophytic Fungi of Tall and Meadow Fescues on Biological Control of Mealybug (Phenococcus solani Ferris, Hom.:Pseudococcidae)

Endophytic fungi, Neotyphodium spp. symbiotically infect host grasses, Fescue arundinacea Schreb. and F. pratensis Huds. and Mealybug, Phenococcus solani Ferris attacks some forage plants. To evaluate the role of these fungi to control this pest, four genotypes of F. arundinacea and two genotypes of F. pratensis were used. Plant tillers were split into two sections, one section of which was freed from endophyte using a fungicide mixture. The mixture contained 2 grams of active ingredients of Propiconazol and 1 ml of Folicur per liter of water. New tillers from endophyte-infected and endophyte-free plants were transferred into the field. The number of mealybugs was measured after the first visible sign of infestation on roots. To count mealybug, one plant hill of each plot was randomly selected. Hay yield of each plot was measured by clipping the plants 5 cm above ground level. Correlation of hay yield and other growth characteristics with the number of mealybugs on roots as an index for mealybug damage on infested plants was determined. The results indicated that endophyte-free plants were highly infested with mealybug, P. solani compared with endophyte-infected plants that were completely free of P. solani, correlation coefficients showed that there was significant negative correlation between forage yield and mealybug numbers, indicating mealybug damage on infested plants. It seems that endophytic fungi are effective biocontrol factors for some root feeding pest such as mealybug, P. solani.