211 Karnataka J. Agric. Sci., 23(1) : (211-212) 2010 Biology of eucalyptus gall wasp, Leptocybe invasa Fisher and La Salle (Hymenoptera: Eulophidae) Since 2000 a new invasive pest is wreaking havoc on eucalyptus plantations throughout the world. First reported from northern and eastern Africa, the Middle East and Mediterranean countries, the pest has expanded its range like wild fire in every continent. Presumed to have originated from Australia, the pest was subsequently identified as a gall wasp, Leptocybe invasa Fisher & La Salle (Hymenoptera: Eulophidae) (Mendel et al., 2004). In India it was first noticed in 2001 at Mandya district in Karnataka and later in 2002 at Marakkanam in Villupuram district of Tamil Nadu. It was also reported from Andhra Pradesh, Kerala, Pondicherry, Gujarat, Madhya Pradesh, Uttar Pradesh, Maharashtra, Goa, and Delhi (Kumar et al., 2007). Adult female measures 1.1 to 1.4 mm and lays eggs inside tender leaves and stem. Larvae after hatching out of eggs remain in a cavity formed within the plant tissues and feed on the tissues which results in formation of galls. The pest attack was observed in nurseries, coppice shoots and young plantations. The affected seedlings show stunted growth and become unsuitable for planting (Mendel et al., 2004). On heavily attacked young trees the canopy hangs due to the weight of gall (http//www.fao.pdf.). The practice of raising nursery for planting new areas coupled with coppicing provides large amounts of young leaf and shoot material ideal for L. invasa infestation favouring large population build-up and consequent higher levels of damage. Even after a decade of its existence not much work has been done on this pest hence present studies on biology and behaviour were undertaken at Department of Agriculture entomology, University of Agricultural Sciences, Dharwad during 2009. The investigations were carried out at the Department of Agricultural Entomology, College of Agriculture, University of Agricultural Sciences, Dharwad during 2009. Observations in the field and nursery on various aspects of the biology and behavior like period of activity, oviposition and gall development were recorded both in the laboratory and the main field. For laboratory studies, infestation free seedlings were kept in a glass jar and were subjected to oviposition for 48 hr. Ten female adults were released into the jar for oviposition. To study the biology in the green house four highly susceptible E. tereticornis plants were pruned during April 2009 and covered with pin holed polythene cage to avoid natural infestation. After the emergence of the coppice, ten adults were released into the cage. Observations on oviposition damage, number of days for oozing from oviposition site, tissue disruption, gall development, discoloration of the gall and texture of the gall till emergence of the adults from the galls as per the description given by Mendel et al. (2004) were recorded daily. To know the adult longevity, ten adults were released in a test tube covered with muslin cloth with three replications and the mortality of adults was recorded daily. Measurements of the insect was done using Lieca M165 stereo zone microscope with Lieca suite 4.0. Observations revealed that though L. invasa adults were active throughout the day, however, activity was more during sunny hours (after 9.30 am in the morning and after 2.30 pm in the evening). The insect laid eggs on young parts of the plant viz. leaf midrib, petiole and tender shoot. The damage was very severe in nursery seedlings and coppice (36.99 galls/10 cm shoot) than on grownup trees (15.67 galls/10 cm shoot). Heavy egg load due to repeated oviposition resulted in little leaf appearance and stunted growth. In severe cases the tips of the seedlings and coppice dried up. Oviposition damage was noticed even at a height of 15 m above the ground level on six year old trees. Egg lying was noticed even on buds within three day of bud burst. Only females emerged from the galls and started laying eggs indicating thelytokous reproduction. However, a lone male was encountered during October 2008. During subsequent observations a small number of males (2-5) were regularly recoded. Males measured 1.28 mm (range 1.21 to 1.37) in length, head length was 0.28 mm (range 0.22 to 0.33) and width 0.29 mm (range 0.24 to 0.36 mm), thorax length was 0.52 mm (0.48 to 0.55 mm), width 0.29 (0.28 to 0.31) and abdomen length was 0.51 mm (0.47 to 0.55 mm), width of the abdomen was 0.32 (range 0.31 to 0.33 mm). Antennae measured 0.49 mm (range 0.46 to 0.52 mm) the antennae consisted of three claval, four funicular and three ring segments. The females measured about 1.2 mm to 1.4 mm. In the laboratory the adults readily laid eggs on mid ribs, petiole and tender stem of the seedling. White ooze at oviposition site was evident within seven days after oviposition. Seedlings in the glass jar exposed for oviposition showed scarring of tissue within 12-15 days after oviposition. However, further development of galls was not noticed even after three months. Table 1: Biology of eucalyptus gall wasp, Leptocybe invasa on Eucalyptus tereticornis Stage Range (Days) Mean ± SD (Days) Oviposition - ooze 5-7 6.5 ± 1.20 Ooze - I stage 7-8 7.4 ± 2.98 I - II 6-8 4.8 ± 1.47 II - III 12-13 11.20 ± 1.60 III - IV 15-17 16.75 ± 1.83 V 9-12 7.00 ±1.53 Total 54- 65 59.5 ± 1.56 . Sl.No. 1 2 3 4 5 6