PEST-MAN: a forecasting system for apple and pear pests1

To achieve satisfactory management of insect pests of apple and pear, growers must accurately establish the necessity for control actions such as supplementing natural enemy numbers or applying pesticides, and the optimal timing for these actions. Inaccurate determination of these questions can lead to unnecessary or inefficient actions being taken, with undesirable environmental and financial consequences. A project, funded by the British Apple and Pear Research Council, began in 1988 to describe mathematically the population dynamics and phenology of several apple and pear pests. The objective of the research was to develop a suite of simulation models to be used in conjunction with automatic meteorological monitoring equipment to provide a rational basis for decision making in pest management. The models have been thoroughly validated using historical results of pest populations in orchards in south-east England. Output from the models has been satisfactorily accurate, and as a result a delivery system for the models has been developed. This package, named PEST-MAN, has an intuitive style of presentation involving simple pull-down menus, context-sensitive help statements and colour graphics, and allows users to familiarize themselves quickly with the system.     

Dietary structured lipids for post-weaning piglets: fat digestibility, nitrogen retention and fatty acid profiles of tissues

In four groups of post-weaning piglets the effects of triacylglycerol structure and fatty acid profiles of four dietary fats on apparent faecal nutrient digestibility, nitrogen retention and fatty acid profiles of platelet and erythrocyte membranes, liver, adipose tissue and skeletal muscle were examined. Dietary fats included as 10% (w/w) of the diets were two structured fats of rapeseed oil interesterified with tridecanoin (R1) or coconut oil (R2), respectively, one mixture of rapeseed oil and coconut oil (R3) and rapeseed oil as control (R4). Faeces and urine from piglets weaned at 28 days of age were collected quantitatively during three periods each of 5 days, in which the piglets were kept in metabolism cages for measurement of apparent faecal nutrient and energy digestibility and nitrogen retention. Apparent faecal fat digestibilities were significantly improved in groups fed interesterified fats or the physical mixtures (R1, R2 and R3) compared with rapeseed oil (R4). Apparent faecal nitrogen digestibility and retention were similar in all four groups in the three periods, but increased with time. Apparent faecal fat digestibilities were significantly improved from the first to the third week in the groups R1 and R2. Fatty acid profiles in platelet and erythrocyte membranes and in tissues reflected the fatty acid profile of the dietary fat, except for medium-chain fatty acids, which were only found in low proportions, indicating that 10:0 was mainly used as an energy source.     

Electrophysiological Studies of the Cutaneous Innervation of the External Genitalia of the Male Dog

The external genitalia and perineum of the male dog receive cutaneous innervation from the caudal cutaneous femoral, superficial perineal and genitofemoral nerves and the dorsal nerve of the penis. In addition the cranial and caudal iliohypogastric nerves occasionally supply the prepuce. Considerable overlaop between adjacent cutaneous areas, particularly on the prepuce, is noted and the extent of all cutaneous areas is greater and more expansive than previosly described. Only the cutaneous area of the genitofemoral nerve is reduced from earlier accounts, being restricted to the prepuce, inguinal region, and medial thigh but never supplying the scrotum.     

Control of Verticillium dahliae on tomato in Tunisia by resistant cultivars and soil disinfestation1

Verticillium dahliae is an important soil-borne pathogen of vegetables in the central coastal region of Tunisia. Cultivation of resistant tomato cultivars does not always give satisfaction as they do not fulfil agronomic requirements (earliness, fruit size and yield). Soil treatment with dichloropropene/methyl isothiocyanate mixture (36.12 g + 16.45 g m^-2) gave excellent control of verticillium wilt and nearly tripled the yield of the susceptible cultivar H63–5. Dazomet (60 g m^-2) caused only slight disease depression and less yield increase. Parmi les pathogènes édaphiques des cultures maraîchères, Verticillium dahliae occupe une place importante dans le Sahel tunisien. Bien que les cultivars résistants donnent entière satisfaction sur le plan phytopathologique, leur utilisation est limitée à cause de leurs faiblesses agronomiques (précocité, calibre des fruits et rendement). La désinfection du sol avec le mélange dichloropropène/méthyl-isothiocyanate (36, 12 g + 16,45 g m^-2) réduit considérablement la verticilliose et triple presque le rendement de l'hybride sensible H63-5. L'incidence du dazomet (60 g m^-2) sur la trachéomycose et le rendement était moindre.