Solarization; a physical control method for weeds and parasitic plants (Orobanche spp.) in Mediterranean agriculture

Summary. Experiments were conducted between 1985 and 1988 to evaluate the effect of duration and time of solarization on the control of two broom rapes ( Orobanche aegyptiaca Pers., O. crenata Forsk.) and other weeds common in the fields of faba bean ( Vicia faba L.) and lentil ( Lens culinaris Medik.) in West Asia. Solarization was performed by applying clear polyethylene sheet to the soil for 0, 10, 20, or 40 days in 1985/86, 0, 30, or 40 days in 1986/87 and 0, 20, 30, 40 or 50 days in 1987/88 during the hot season (July and August) and for 50 days immediately before sowing during milder weather (September and October) in 1986/87. Best control was obtained with solarization for 30–50 days in the hot season. Maximum soil temperature under polyethylene at 5 cm was 55°C in 1985, 48°C in 1986 and 57°C in 1987. Broomrape dry weight decreased in the first experiment by more than 90% in both faba bean and lentil fields. Solarization controlled broom-rape and other weeds in the following two seasons when the soil was left undisturbed during the season of the treatment.     

Disinfection of Flower Bulbs by Pesticides in Foam1

Disinfection of flower bulbs is a very important operation for the grower. Traditional methods like spraying or drenching the bulbs with pesticide solutions is very environment-polluting. To overcome the release of pesticides into the environment by dumping wastes, research has been undertaken into an alternative method of disinfection: administration of pesticides in a foam formulation. If applied properly this method avoids overdosing and prevents leakage of pesticides to the ground and drift of droplets. Several characteristics of the foam have been studied in relation to this method' of treatment. Other possibilities of application of this method are considered.     

UNTERSUCHUNGEN ZUR KONKURRENZWIRKUNG VON KULTURPFLANZEN UND UNKRAUTERN AUFEINANDER

Summary. Pot experiments on the competitive effects of charlock (Sinapis arvensis L.) on oats and wild oat (Avena fatua L.) on barley had the following results:
(1) During the period up to tillering there was an appreciable effect of the weeds on crop growth with depression in plant weight of 10–15% from that in the absence of weeds.
(2) The greatest competitive effect occurred up to the middle of shooting of the cereals, when there were depressions in plant weight of 25–32%.
(3) After this stage, the competitive effects of the weeds were much less in pots with a high nutrient level, and at low nutrient level there was almost no competitive effect.
(4) The reduction in growth at the time of weeding was somewhat less at the low nutrient level than at the high nutrient level, and it is concluded that at the high level the competitive ability of the weeds was favoured more than that of the cereal crops.
(5) The cereals were not able to overcome the initial damage caused by the weeds even when the weeds were removed at the beginning of tillering. A partial recovery did how ever occur at the high but not at the low nutrient level.
(6) Both combinations, oats with charlock and barley with wild oat, behaved similarly, but some differences could be observed.
Compétition entre plantes cultivées et mauvaises herbes II. Action des mauvaises herbes annuelles sur les céréales     

Untersuchungen zur Keimungsbiologie von sechs tropischen Segetalarten

Investigation of the germination of six tropical arable weeds With the six tropical arable weeds studied, Ageratum conyzoides, Blechum brownei, Crassocephalum crepidioides, Mikania micrantha, Paspalum conjugatum and P. paniculatum, the lowest temperatures at which germination occurred were in the range 10–15(20)°C, the highest up to 40°C, with the optimum between 20°C and 35°C. Ageratum conyzoides and C. crepidioides had lower limits of germination temperature than the other species, which explains their comparatively greater incidence at high altitudes. The germination temperatures of both representative temperate species, Alopecurus myosuroides and Chenopodium album were 5 (minimum), 15–25 (optimum) and 40°C (maximum). The germination of A. conyzoides, C. crepidioides and M. micrantha was reduced by an osmotic potential of - 1 bar. At -4·7 bar only P. paniculatum of the tropical species germinated to a small extent whilst Al. myosuroides and Ch. album were not affected. After storage for a year in dry conditions all six tropical species only germinated when exposed to light. After 20 months, C. crepidioides and P. paniculatum would also do so in the dark.     

Establishment of Integrated Control Systems1

The integration of special measures into a system requires the evaluation of their absolute and relative importance. Processes have to be known and ways of their mathematical simulation are necessary. The very first steps have been done in this direction in weed science. One of the key factors for such simulations is the population dynamics of weeds and within this the dynamics of reproduction and survival is of special importance. Integrated control systems can be established. They could be much improved with a better understanding of the key factors and the interrelationships involved.     

Atracurium as an Adjunct to Halothane-Oxygen Anesthesia in a Llama Undergoing Intraocular Surgery A Case Report

Atracurium (0.2 mg/kg intravenously [IV]) was administered to a llama anesthetized with halothane in oxygen, to insure immobilization of the globe during intraocular surgery. Recovery of neuromuscular function was facilitated by administration of edrophonium (0.5 mg/kg IV).     

Periodic inspection of air-assisted sprayers1

Periodic inspections of air-assisted sprayers have been carried out i n Germany since 1984. The inspection follows BBA Guideline no. 44 and includes measurement of pump function and single nozzle output. a check o n pressure gauge operation and other visual checks. Similar systems have been implemented or are under consideration in other countries. There is discussion throughout Europe on the inclusion of a vertical patternator into the inspection procedure, to measure and optimize the vertical liquid distribution pattern with respect to an individual application situation. The original idea of the sprayer inspection was to improve the equipment and to save repair time during the spraying season. Environmental aspects were stressed later. The introduction of the mandatory periodic inspection of field sprayers in Germany was justified by the aim of avoiding chemical pollution due to deficient spraying equipment. A 4-year test programme with air-assisted sprayers in Germany has now proved that vertical patternators are not appropriate for specific adjustment of sprayer to particular crop situations. It is concluded that this equipment should not be a generally required test stand for periodic sprayer inspections.