The history of the chemical control of terrestrial gastropods; mode of action of molluscicides, including its neurotoxic, desiccating and cytotoxic (on mucocytes of the digestive tract and skin, digestive gland cells and epithelial cells of the oesophageal crop) properties as well as its inhibiting effect on enzymes and energy metabolism; laboratory, terrarium and field evaluation of molluscicidal activity; and methods of molluscicide application are discussed.

Ryegrass swards at fourteeo widely separated sites in England were assessed for yield, botanical composition and invertebrate populations, with and without insecticide treatment during a 4-year period. Treatment with insecticide reduced the numbers of almost all invertebrate groups sampled and increased grass growth at some time at all but one site. Annual DM output was increased by 0-32% depending upon the site concerned. Evidence is presented which suggests that the yield increases were due to the suppression of aphids, plantsucking bugs, stem-boring fly larvae, and perhaps nematodes.

SummaryTest materials were incorporated in wheatflour pellets to measure their effect on slug feeding. The dry weights of individual pellets were measured before and after exposure for 24 h to starved slugs. The method gave consistent results, and can accommodate test materials with different physical properties. The phagostimulant effect of sucrose was confirmed. An extract of the herb tarragon (Artemisia dracunculus) was the most effective antifeedant of the materials used at the concentrations tested. The method is compared with other published techniques.

Abstract. 1. Capture efficiency was determined chiefly by insect type: Diptera 79–98%, Hymenoptera 60–83%, Homoptera 32–76%, Thysanoptera 27–62%, Acarina 12–40%.2. Grass length also affected efficiency, but to a lesser degree.3. Prolongation of the sampling period increased the proportions of some groups more than others.4. Capture efficiency for any group was not affected by the number of individuals present.5. Catch size did not vary with time of day.6. The method was unsatisfactory for wet grass.

Plots were sown with six varieties of perennial ryegrass, one each of Italian, Westerwolds and hybrid ryegrass, and one each of cocksfoot and timothy, in April 1974. D.M. yield was assessed at four cuts each year, on plots receiving 300 kg N/ha annually, for 4 years. Invertebrate populations and plant survival were monitored at intervals. Half the plots were treated regularly from sowing onwards with the systemic insecticide, phorate. Insecticide treatment increased output generally, but the extent varied from year to year and between grass varieties. The persistence of Italian and hybrid ryegrass varieties was dramatically improved by insecticide treatment. The three diploid varieties of perennial ryegrass studied appeared to be less susceptible to pest damage than the three tetraploid varieties. Shoot-fly larvae (Diptera: Chloropidae) were the major obvious cause of damage.