“The injury caused by potato beetles is the defoliation of potato plants especially under warm and dry weather conditions. A single larva can destroy up to 40 to 50 cm’ of the leaf surface which corresponds to 1 % to 2 % of the leaf area of plants at the developmental stage appearance of blossom””. The yield loss due to one larva is approximately 0.6 %. The economic injury level is reached on average with five larvae per plant. Treatments with insect growth regulators or Bacillus thuringiensis are justified when 30 % of the plants ore attacked by young larvae (L] -L2). With other insecticides, the threshold value is reached at a defoliation rate of 10 to 20 %.”
Symbiotic nitrogen fixation by bacteria in the soil coexisting with legumes leads to reduced fertiliser requirement. It is not easy to measure this variable on farms, however. Now researchers from Agroscope have developed a method for estimating nitrogen input via symbiotic fixation at farm level.
With increasing global and regional temperatures, even in Switzerland the growing season has lengthened considerably. Using data from the Federal Office of Meteorology and Climatology, Agroscope has traced the development of the growing season since the start of the previous century.
The phosphate mineral reserves required for fertiliser production could be exhausted on a global scale in just a few decades. This study presents a method for recycling a Swiss industrial by-product into a phosphate fertiliser.