Hou valse meeldauw eronder

Onlangs is een aantal uienrassen geïntroduceerd met resistentie tegen valse meeldauw. Maar zolang deze en andere ziekten nog niet zijn uitgebannen, blijven preventie en accurate bestrijding de sleutelwoorden. Het PPO-AGV zet de belangrijkste aantastingen op een rijtje. Valse meeldauw staat met stip op één

Experimental control strategies reducing the fungicide input at a practical scale

Phytophthora infestans is the most devastating disease in potato cultivation. Chemical control is necessary to ensure a healthy crop. At the same time Dutch governmental policy asks for a reduction of the environmental impact of potato late blight control by 75% in 2012 as compared to 1996-1998. The aim of the experiments was to compare Decision Support Systems with different approaches to blight risk management for their ability to reduce the fungicide input without compromising control efficacy. Considerable savings, up to 81% when compared to weekly, full dose rate, spray schedules, can be achieved by using information on cultivar resistance, length of the critical period and disease pressure to decide whether or not to spray. The subroutine calculating the potential for viable transport of spores is only effective on resistant varieties as the threshold was exceeded with every critical period on less resistant cultivars. Implications of the experimental control strategies for agricultural practise are discusse

Curatieve en eradicatieve (stop) werking van fungiciden tegen Phytophthora 2009

Er zijn 2 pottenproeven uitgevoerd, waarbij in de ene proef de curatieve werking en in de andere proef de eradicatieve (stop) werking van fungiciden of fungicidencombinaties werd onderzocht

Gebruik van Ulocladium atrum in een bestrijdingstrategie op basis van een BOS tegen vruchtrot in aardbeien

Een Beslissing Ondersteunend Systeem werd succesvol geïntroduceerd om de bestrijding van Botrytis cinerea in aardbeien met de antagonist U. atrum te verbeteren. Optimalisatie van de strategie was nog wel nodig omdat bij het inzetten van alleen de antagonist het niveau van chemische bescherming doorgaans niet gehaald wordt. Door bij een hoge infectiedruk met een fungicide te spuiten en bij een matige infectiedruk de antagonist in te zetten werden goede resultaten verkregen. In het licht van de residuproblematiek zou het wenselijk zijn dat niet-chemische alternatieven commercieel verkrijgbaar zijn. U. atrum heeft op dit moment echter nog geen toelating voor toepassing tegen Botrytis in Nederland

Effect of polythene Tunnels and Cultivars on Grey Mould Caused by Botrytis cinerea in Organically Grown Strawberries

The effect of covering the crop with polythene tunnels on Botrytis fruit rot was investigated. Two cultivars were grown organically in three field experiments during 2001-2003. Botrytis cinerea is a major threat to strawberry cultivation in the field, especially when the crop is grown organically. Control of the disease in organic strawberry crops depends merely on prevention. Botrytis infection risk depends on humidity and temperature. Under optimal temperature conditions leaf wetness period necessary for infection of strawberry flowers decreases (Bulger et al., 1997). Prevention or shortening of the leaf wetness period might help to reduce infection risk of strawberries. Cv. Elsanta proved less susceptible to B. cinerea than cv. Darselect, thus choosing an appropriate cultivar is a helpful means to control grey mould. Covering the crop with polythene tunnels effectively reduced the infection risk of B. cinerea on strawberry flowers. Mechanisms to regulate the temperature in the tunnel are necessary to ensure fruit quality and should be investigated further

Beregenen op Maat

In de periode 1996 tot en met 1998 is door het PAV in het zuidoosten van Nederland onderzoek gedaan binnen het project "Beregenen op Maat". Achterliggend doel van de provincies Noord-Brabant en Limburg was het verbruik van grondwater terug te dringe

Acclimatization to high-variance habitats does not enhance physiological tolerance of two key Caribbean corals to future temperature and pH

Corals are acclimatized to populate dynamic habitats that neighbour coral reefs. Habitats such as seagrass beds exhibit broad diel changes in temperature and pH that routinely expose corals to conditions predicted for reefs over the next 50–100 years. However, whether such acclimatization effectively enhances physiological tolerance to, and hence provides refuge against, future climate scenarios remains unknown. Also, whether corals living in low-variance habitats can tolerate present-day high-variance conditions remains untested. We experimentally examined how pH and temperature predicted for the year 2100 affects the growth and physiology of two dominant Caribbean corals (Acropora palmata and Porites astreoides) native to habitats with intrinsically low (outer-reef terrace, LV) and/or high (neighbouring seagrass, HV) environmental variance. Under present-day temperature and pH, growth and metabolic rates (calcification, respiration and photosynthesis) were unchanged for HV versus LV populations. Superimposing future climate scenarios onto the HV and LV conditions did not result in any enhanced tolerance to colonies native to HV. Calcification rates were always lower for elevated temperature and/or reduced pH. Together, these results suggest that seagrass habitats may not serve as refugia against climate change if the magnitude of future temperature and pH changes is equivalent to neighbouring reef habitats

Stoombehandelingen eerstejaars plantuien tegen valse meeldauw

In de winter van 2010-2011 zijn in opdracht van het Productschap Akkerbouw verschillende stoombehandelingsvarianten bij Ruvoma uitgevoerd. Namelijk bij 40, 42.5 en 45 ∘C, bij 85 en 95 % RV en gedurende één en twee dagen. De uitjes zijn vervolgens in een biotoets in de kas getoetst op kieming en systemische aantasting

Development and Psychometric Properties of an Assessment for Persons With Intellectual Disability—The interRAI ID

This paper describes the development of the interRAI-Intellectual Disability (interRAI ID), a comprehensive instrument that assesses all key domains of interest to service providers relative to a person with an intellectual disability (ID). The authors report on the reliability and validity of embedded scales for cognition, self-care, aggression, and depression. Four provider agencies volunteered to participate and assessed a total of 160 community-dwelling adults with ID using the interRAI ID, Dementia Questionnaire for Persons with Mental Retardation, and Reiss Screen for Maladaptive Behavior. All scales had acceptable levels of internal consistency (Cronbach’s alpha 0.74–0.93) and good relationships with the criterion measures ( r  = 0.50–0.93, p  < 0.0001). The development of the interRAI ID represents an important and successful first step toward an integrated, comprehensive, and standardized assessment of adults with ID. Use of this instrument may lead to more appropriate support planning, enhanced communication between various professionals supporting persons with ID, and a more seamless approach to supports across the health and social service systems.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/75618/1/j.1741-1130.2006.00094.x.pd