April 1953 , ET-307 
 
 United States Department of Agriculture 
 
 Agricultural Research Administration 
 
 Bureau of Entomology and Plant Quarantine 
 
 A SIMPLE METHOD FOR REARING GREEN 
 JUNE BEETLE LARVAE 
 
 By Wayne L. Howe, Division of Cereal and Forage Insect Investigations, 
 and William V. Campbell, Virginia Agricultural Experiment Station, 
 Tidewater Field Station 
 
 Larvae of the green June beetle ( Cotinis nitida (L.)) have recently 
 become important pests of ladino clover in Virginia and other south- 
 eastern States. During the course of tests with insecticides at the 
 Virginia Tidewater Field Station in 1952, a simple technique was devel- 
 oped for rearing these larvae. With this technique it was possible to 
 observe closely the effects of different dosages of insecticide on all 
 three larval instars. This rearing technique could be readily adapted 
 to biological studies requiring detailed observations of larval activities 
 and responses. 
 
 Collection and Incubation of Eggs 
 
 Field collections of adult beetles were made as the first step in 
 obtaining eggs of similar age. The sexes could be distinguished rapidly 
 and reliably in the field because the female has three prominent outer 
 tibial spurs on the front legs and the male only two. One to three fe- 
 males and three to five males were placed in each cage, after which 
 mating occurred. 
 
 The cages were large lantern globes fitted closely to the top of fire- 
 clay pots 6 to 7 inches in diameter. The top of each globe was covered 
 with cheesecloth. Each pot was filled with slightly moistened sandy 
 soil. Ripening fruit such as blackberries, peaches, or sliced apples 
 was supplied as food for the ovipositing beetles. 
 
 After oviposition the soil was removed from the pots and examined 
 for eggs at intervals of 1 to 5 days, depending on the desired accuracy 
 of oviposition data. The large, easily visible eggs were found distrib- 
 uted throughout more or less compact earthen balls. 
 
 These eggs were transferred individually for incubation to metal 
 salve boxes, 2 inches in diameter, half full of slightly moistened sandy 
 soil and covered with tight-fitting lids. From 20 to 25 eggs were placed 
 in each box after it had been observed that under prolonged hunger one 
 or two newly hatched larvae would devour many unhatched eggs. The 
 
boxes containing the eggs were then placed on a concrete floor where the 
 temperature remained at approximately 75-80° F. As soon as possible 
 after hatching, the larvae were transferred to larger rearing containers. 
 Throughout the rearing season the incubation period varied only slightly 
 from 13 days. 
 
 Handling and Feeding Larvae 
 
 Larvae may be reared in different types and sizes of open containers 
 suitable for holding moistened soil. In this method, boxes 17 inches 
 square and 5 inches deep, with wooden sides 3/4 inch thick and bottoms 
 of composition pressed wood, were partitioned into four equal compart- 
 ments (fig. 1) with removable, interlocking strips of composition pressed 
 wood. These compartments permitted close observations of the reactions 
 of all three instars to different dosages of insecticides. Each compart- 
 ment was filled with light sandy soil to a depth of 3 inches. A container 
 could hold 60 to 100 first-instar, 30 to 40 second-instar, and 15 to 20 
 third-instar larvae until full-grown. Removing the partitions made it 
 possible to use the entire box for rearing larger numbers of third-instars. 
 All rearing was done in an out-of-door insectary. 
 
 The larvae were placed in the compartments and soon burrowed into 
 the soil. After they had entered the soil, dehydrated alfalfa meal con- 
 taining 15 percent of crude protein was sprinkled over the surface at 
 intervals of 1 to 3 days depending upon how fast they consumed it. This 
 food was not mixed with the soil but was moistened daily with a sprinkling 
 can, usually late in the afternoon. This operation assisted in maintaining 
 a favorable soil-moisture content. A saturated soil-moisture condition 
 should be avoided. 
 
 Approximately 1,300 larvae were successfully reared by this method. 
 
Figure 1.- -Container for rearing green June beetle 
 larvae, viewed from above. 
 
JNIVERSITY OF FLORID* 
 
 3 1262 09242 9173