Eggplant Integrated Pest Management AN ECOLOGICAL GUIDE

__________________________________________________________________________________Major Eggplant Insect Pests5.7 Leafroller - Eublemma (Autoba) olivaceaSee photos 14, 15, 16 (page 176).Scientific name: Eublemma olivacea or Autoba olivaceaDescriptionCaterpillars are purple-brown with many cream-colored hollow bumps and long hairs on the back andsides. The adult is an olive green moth that is active at night.The caterpillar can be found inside the rolled leaf, where it chews on the leaf surface.Life cycleThe female moth lays eggs in masses on the young leaves. Each mass may have 8 – 22 eggs. Thecaterpillar feeds for about 4 weeks and then pupates inside the rolled leaf. In favorable climates theremay be 3 to 4 generations each year.Host rangeSolanaceous plants.Plant damage and compensationYoung leaves are rolled lengthwise. Rolled leaves are brown and eventually dry. In heavy infestationsentire portions of plants appear brown and leaf drop occurs. When the leaves turn brown or drop, theplant will have less leaf area for the energy production (photosynthesis). Less energy will result in weakerplants and lower or even no production.At some locations plant infestation can be very high, e.g. in the late ’96 seasonin Assam, India, 65% plant infestation was reported. In general however,leafrollers seldom pose a threat to crop development and yield.Natural enemiesThe wasp Cotesia sp. is a larval parasitoid of leafroller. This wasp was found infield studies in Mymensingh, Bangladesh in 1998.Cotesia wasp oncaterpillarManagement and control practicesPrevention activities:• Grow a healthy crop: strong, healthy plants can resist insect pests and diseases better. Healthy plantscan probably compensate for loss of leaves by leafroller. See section 4.5.• Changing planting dates: Field tests in Assam, India, showed that the incidence leafroller on eggplantwas lowest on late (Nov.- Dec.) planted crops (Bohra, 1995).Once leafrollers are found in the field:• When low numbers are found, handpicking the infested leaves and destroying them outside the fieldmay be an option.• Nematodes that kill insects, such as Steinernema sp., may be a control option when these nematodesare available. See section 6.3.4 on nematodes.Points to remember about leafroller:1. In general, leafrollers seldom pose a threat to eggplant crop development and yield.2. Handpicking and destroying infested leaves helps reduce populations.3. The parasitoid Cotesia sp. has been found parasitizing leafroller larvae.Related exercises from CABI Bioscience/FAO Vegetable IPM Exercise Manual4.1. Insect zoo – life cycle study4-A.3. Plant compensation90Eggplant Ecological Guide