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IntroductionThis is the first of a series of papers dealing with investigations that were commenced in 1956 at Summerland, British Columbia, to determine if the codling moth, Carpocapsa pomonella (L.), could be eradicated in the interior of British Columbia by the release of sexually sterile male moths.One of the most important prerequisites for the success of this method is the development of a techni ue that will sterilize the male without seriously affecting its behaviour, particular ' I v mating ability and longevity. Complete or almost complete sterility has bekn induced in one or both sexes of certain species of insects bv feeding them chemicals (LaBrecque et al., 1960), or by exposing them to Xo r gamma rays (Bushland and Hopkins, 1953), or by subjecting them to abnormally high temperatures (Riordan, 1957).This paper reports exploratory experiments in which mature larvae, pupae, and adult codling moths were subjected to abnormally high temperatures to determine if heat could be used to induce sterility. Materials and MethodsLarvae of the codling moth were reared on immature apples that were continuously exposed to fluorescent light. The light intensity was at least 15 footcandles at the surface of the apples facing the light source. T h e temperature varied from 75" to 85°F. As the mature larvae left the apples they were allowed to spin u p in narrow strips of corrugated paper. Every second day, the larvae were removed from the paper, sexed (the blackish testes could be readily observed through the integument), and allowed to respin in slotted, thin wooden strips backed with glass. Every day, the insects that had pupated within the last 24 hours were removed from the wooden strips (the brownish pupae could be easily seen through the glass), and each pupa placed in a shell vial, 2.5 inches tall and 0.6 inch in diameter. The mouth of each vial was covered with a piece of openmeshed cloth, and the vials were then left undisturbed until adult emergence. The sexed larvae, pupae, and adult moths, hereinafter called "normal" insects, were kept at 70 +-1°F. and 50 +-5 per cent relative humidity.Cages in which adults were allowed to mate and oviposit were generally ten inches tall and six inches in diameter. These cylindrical cages were constructed of wire screen, o r of celluloid, and lined with "Scott Cut-rite" waxed paper3. (Mating and oviposition were unsatisfactory with some other brands of waxed paper.) T w o other types of cages were also used. One of these consisted of a Manila paper bag, the mouth of which was sealed with a sheet of clear cellophane; the other was made entirely of waxed paper. The dimensions of the former were 12 by 6.5 by 4 inches, and the latter 11 by 6 by 6 inches. One-gallon glass jars were occasionally utilized as cages when all the other types of cages were in use. lcontribution No. 71, Research Station, Research Branch, Canada Department of Agriculture, Summerland, British Columbia. 2Entomologist and Technician respectively. awestminster Paper company' Limited, New Westminster, B.C....

Codling moth, Cydia pomonella (L.), control by sterile insect release (SIR) was assessed in 320–526 ha of apples and pears in the Similkameen Valley, B.C., from 1976 to 1978. In preparation for SIR, the moth population was first reduced to low numbers by removal of neglected trees in 1972 and by chemical sprays in 1975. Sterile (35 krad) male and female moths were released in each orchard 2 or 3 times weekly from 1 May until early September. A total of 23,600 sterile moths/ha was released in 1976, 36,500 in 1977, and 31,800 in 1978. Populations of sterile (marked) and wild moths were monitored by sex pheromone traps, and damage was assessed by fruit examination at harvest. Control was very good except for a few orchards in which overwintered populations were too high to achieve adequate overflooding with sterile moths. Damage exceeded the economic threshold (0.5%) in only 1 of 86 treated orchards in 1976, in 6 of 193 orchards in 1977, and in 0 of 157 orchards in 1978. Results in 32 orchards showed that when wild populations are brought close to extinction all codling moth control measures can be omitted for 2 or more years depending on degree of orchard isolation. Omission of codling moth sprays from 1976 to 1978 did not result in any important change in population levels of other apple pests. Cost of control by SIR was ca. $225/ha per year vs. ca. $95 for chemical control.

An artificial diet for rearing the codling moth is described. It is a modification of a casein–wheat germ diet that was initially developed for the cabbage looper. Agar was replaced by a mixture of wood sawdust, wheat flour, and wood pulp. Growth of microorganisms was controlled by sorbic acid and aureomycin, and by lowering the pH of the diet to 3.5 with citric acid. Production cost for dietary ingredients was about $1/1000 moths. The moths were slightly smaller than those reared on apple. When confined in cages, the sterilized diet-reared moths were somewhat less competitive than the apple-reared insects. However, sterilized diet-reared male moths released in an apple orchard dispersed more rapidly than sterilized apple-reared males.

This is the third paper in a series dealing with investigations, initiated in 1956, to determine if the codling moth, Carpocapsa pomonella (L.), might be eradicated in the Okanagan and Similkameen Vallevs of British Columbia by the release of sexually sterile moths. In the first twoe papers exposure to heat (Proverbs and Newton, 1962) and to gamma radiation (Proverbs and Newton, 1962a) were examined as methods of inducing sexual sterility. Heat was not satisfactory. However, exposure of fully developed pupae to 40,000 rads of gamma radiation induced almost complete sexual sterility (used in the broad sense) in the male moth without causing undesirable side effects. The female was more easily sterilized than the male.