THE INFLUENCE OF TEMPERATURE ON THE VERTICAL DISTRIBUTION OF THE CITRUS MEALYBUG, PLANOCOCCUS CITRI (RISSO) (HEMIPTERA: PSEUDOCOCCIDAE) ON COFFEE PLANTS

ABSTRACT The knowledge of mealybug distribution on coffee plants improves the monitoring and control efficiency of this pest. The mealybug distribution on coffee plants (Coffea arabica L., cv Mundo Novo), was evaluated at five temperatures. The plant was divided into the following segments: upper part (new leaves, fourth and fifth leaf pair, stalk included), middle part (cotyledons until third leaf pair, stalk included) and bottom part (plant neck and roots). Ten nymphs of second and third instars were placed in equal numbers on the upper and bottom part. Plants were kept in a growth chamber at 15, 20, 25, 30 and 35° C. The mealybugs were counted 7 days after infestation, registering the plant part where they located. Their distribution varied according with the rearing temperature. At 20 and 25° C the insects were distributed evenly; at 15°C they migrated to the bottom part, mainly to the roots; at 30° C they were concentrated at the upper part and at 35° C they were found at the middle part.