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Malacosoma neustria (Linnaeus, 1758) (Lepidoptera: Lasiocampidae) causes economic losses in apple, pear, plum, willow, oak and other economically important trees. In this study, an alphabaculovirus was isolated from the larval population of M. neustria from Samsun in the central Black Sea Region of Turkey between 2015 and 2016. Electron microscope analysis of occlusion bodies (OBs) obtained from dead larvae showed that the nucleocapsids of a new isolate (ManeNPV-T4) are multiply enveloped. The Kimura two-parameter analysis and the phylogenetic tree were performed based on concatenated nucleotide and amino acid sequences of the partial lef-8, lef-9 and polh genes from ManeNPV-T4 isolate compared to those of other 51 baculoviruses. Insecticidal activity tests against third instar M. neustria larvae produced 48 to 100% mortalities. The LC 50 of ManeNPV-T4 was 0.78 x 10 3 OBs/ml in M. neustria . Additionally, the isolate caused mortalities lower than 50% in Spodoptera exigua (Hubner, 1808) (Lepidoptera: Noctuidae) , Lymantria dispar (Linnaeus, 1758) (Lepidoptera: Erebidae) , Hyphantria cunea (Drury, 1773) (Lepidoptera: Arctiidae) and Helicoverpa armigera (Hubner, 1805) (Lepidoptera: Noctuidae) larvae. Consequently, the new nucleopolyhedrovirus is infectious on M. neustria larvae and other lepidopterans.

Laboratory experments and field traits were carried out on the efficiency of selected three con-centrations of each Garlic Gard extract and a mix-ture of chili oil of mustard extract (Valoram) based on fourth instar larvae of the insect. Garlic Gard extract was used in a concentrations of: 1 cm3/L, 0.5 cm3/L and 0.25 cm3/L. The mortality percentages were: 87.5 %, 83.3 % and 66.6 % respectively. The mixture of chili extract and oil of mustard extract was used in a concentrations of : 2 cm3/L, 1 cm3/L and 0.5 cm3/L The mortality per-centages were : 100%, 100% and 73% respect-tively. Garlic Gard extract when used in a field with concentrations of : 8 cm3/L, 6 cm3/L and 4 cm3/L mortality percentages were: 23.3%, 3.3% and 3.3% respectively, and for pupation were : 83.3 %, 49.9% and 36.6% respectively, also the mixture of chili extract and oil of mustard was used in a concentrations of: 20 cm3/L, 10 cm3/L and 7 cm3/L the mortality percentage: 46.6%, 6.6% and 6.6% respectively. And for pupation: 89.9%, 83.3% and 66.6% respectively. Laboratory experiments showed that the mixture of chili ex-tract and of mustard oil was highly effective against insect and more effective than Garlic Gard extract. Field traits showed that both Garlic Gard extract and the mixture of chili extract, and oil of mustard showed repellent effect and Killer materi-als to insects. The mortality percentage was high in using Valoram in comparison with Garlic Gard.

The nuclear polyhedral bodies fromMalacosoma neustria are enclosed within a membrane. The diameter of the nuclear polyhedra varies from 0.9 to 2.8 μ with an average of 1.8 μ. In the nuclear polyhedra the rod-like virus particles occur both singly and in bundles. The single virus rods are enclosed within two membranes, namely the intimate membrane and the developmental membrane. The virus rods which occur in bundles have an intimate membrane just like the single virus rods, whereas the developmental membrane encloses the whole bundle. The virus rods are closely packed by the intimate membrane and between the intimate and the developmental membrane is a space. The diameter of the virus rods without membranes, determined from sectioned polyhedra, is about 25 mμ and the length 250 mμ.

The crystalline material covering the cocoon of Malacosoma neustria testacea (Lasiocampidae, Lepidoptera) was analyzed physically and chemically. The mean component was identified as calcium oxalate monohydrate, and the crystals were found to be whewellite in form.