A fly parasite, Lixophaga diatraeae (Townshend), of the sugarcane borer, Diatraea saccharalis (F.), is currently being produced at our laboratory to determine if it can be released periodically in sugarcane fields and control sugarcane borers. This parasite is reared on sugarcane borers in the laboratory. Frequently more than one parasite develops on a single host insect and host insects vary in size. When several parasites entered the same host some did not develop because of competition between them. This problem was more acute in young host sugarcane borers than in older sugarcane borers. The early 5th stage sugarcane borer larva was the most suitable stage for parasite development. RÉSUMÉ QUELQUES EFFETS DU SUPERPARASITISME DES LARVES DU BORER DE LA CANNE à SUCRE PAR LA TACHINAIRE LIXOPHAGA DIATRAEAE, EN CONDITION DE LABORATOIRE Quand des larves de Diatraea saccharalis (Borer de la canne à sucre) sont parasitées par la Tachinaire Lixophaga diatraeae, la mortalité s'accroît avec l'augmentation du nombre de parasites hébergés par les larves‐hôtes et cela, du début du du début du 1er stade jusqu'au 4ème stade larvaire; cependant la mortalité est plus faible chez les larves les plus âgées au moment de l'attaque du parasite. La durée du développement larvaire des asticots de la Tachinaire est plus courte chez les larves hôtes les plus âgées et diminue également en fonction du nombre de parasites par hôte; toutefois la durée du développement nymphal n'est pas affectée par le superparasitisme. Par contre le poids des pupes du parasite décroît avec la densité du parasitisme. La taille des Tachinaires n'influence pas le choix des partenaires lors de l'accouplement, mais le nombre d'Œufs pondus s'accroît avec le poids des femelles. Le superparasitisme n'affecte pas la longévité du diptère parasite, mais les femelles vivent plus longtemps que les mâles, qu'elles soient issues d'un hôte faiblement ou fortement parasité. Les asticots de Lixophaga muent deux fois à l'intérieur de l'hôte; elles émergent au cours du 3ème stade larvaire pour la pupaison. Une compétition se manifeste entre les asticots, le taux de survie dépendant du nombre de parasites par larve‐hôte, de la localisation des asticots sur le tronc trachéen longitudinal de l'hôte, et de la promiscuité entre ces larves endoparasites.

Highly active feeding (puncturing) stimulant mixtures were formulated for the boll weevil (Anthonomus granáis Boheman) from known cotton constituents, common metabolites, and compounds inducing primary mammalian sensations of taste and odor. Of 286 compounds bioassayed individually, 52 elicited substantial activity, and 14 of these had previously been reported in cotton. The insect was found to express preference for sweet, sour, and cooling taste properties, but odor pref-erences were difficult to establish. Compatability of the individually active components was necessary for formulation of active mixtures. An 8-component mixture of /3-sitosterol, 15-pentadecanolide (15-hydroxypentadecanoic acid (-lactone), 1,8cineole (1,8-epoxy-p-methane), 7V,A-dimethylaniline, vanillin, mannitol, rhamnose, and 0.1M phosphate buffer, pH 7.0, was superior to cottonseed oil and competitive with aqueous bud extract baits.

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Larvae of Diatraea saccharalis (F) were reared on artificial diet in 30-ml cups (1-3 larvae/cup). Adults of the larviparous tachinid parasite, Lixophaga diatraeae (TOWNSEND), were removed from emergence and holding cages with a modified vacuum sweeper. Maggots were extracted from I0 to 14-day-old female flies, that had been disinfected with 1% NaOC1 by one of two methods. In method 1, fly uteri were removed and placed in a 10-ml vial containing a 0.15 ~o agar-water solution with 3-4 glass beads; rapid vibration of the vial ruptured the uteri and distributed the maggots in the agar solution. In method 2, whole flies were blended with 50-ml water in a blender, and maggots were separated from fly particles by screening; then they were suspended in the agar solution. A procedure was devised for determining the number of maggots obtained by each method. The maggot-agar solution was injected into cups containing host larvae and maggots sought out and parasitized the host larvae; however, the percentage producing puparia generally decreased with increases of host larva and/or maggot density. Puparia were harvested from cups by hand and washed in 1 ~o NaOC1 to disinfect and destroy host larval webbing. KNIPL1NG (1972) demonstrated theoretically that the tachinid parasite, Lixophaga diatraeae (TowNSEND), might be used in timed releases to suppress populations of Diatraea saccharalis (F.) in the field. Thus, a rearing program to produce sufficient flies to evaluate this concept was initiated.BENNETT (1969) reviewed the biology, ecology, and laboratory rearing methods for L. diatraeae. Generally, flies were held in cages for emergence, mating, and holding until maggot extraction (L. diatraeae is larviparous, and maggots are physically removed from the fly). Uteri were dissected from flies and placed in a water droplet; as maggots exited from egg shells (hatched), 1-3 were placed via a fine brush on each host larva. Food and water were supplied to the flies daily. These methods were too time consuming and cumbersome for large-scale rearing. During the past 1.5 years rearing techniques reported herein have produced over 900,000 puparia. REARING PROCEDURE HOST REARING. Laboratory rearing procedures for D. saccharalis were generally similar to those described by HENSLEY & HAMMOND (1968). However, larvae were reared in 30-ml plastic cups on soybean-wheat germ diet (10-15-ml/cup) (BREWER, 1976), and eggs, larvae, pupae, and adults were held at temperatures of 26, 28, 26, and 24~ (1) In cooperation with the Delta Branch of the Mississippi Agricultural and Forestry Experiment Station, Stoneville, Mississippi 38776.