P. van Velde

Precision Disease Control in Bed-Grown Crops

Matching spray volume to crop canopy sizes and shapes can reduce the use of plant protection products , thus reducing operational costs and environmental pollution. Developments on crop adapted spraying for fungal control are highlighted in arable crop spraying. A plant-specific variable volume precision sprayer, guided by foliage shape and volume (canopy density sprayer ; CDS ) was developed for bed-grown crops to apply fungicides . Sensor selection to quantify crop canopy and spray techniques to apply variable dose rates are evaluated based on laboratory measurements. Based on the laboratory experience a prototype CDS sprayer was built using either a Weed-IT ® or a GreenSeeker ® sensor to detect plant place (fluorescence) or size (reflectance). Variable rate application was either done with a pulse width modulation nozzle or a switchable four-nozzle body. Spray volume could be changed from 50 to 550 l ha−1 in 16 steps. Spray deposition , biological efficacy and agrochemical use reduction were evaluated in a flower bulb and a potato crop during field measurements using a prototype CDS sprayer. Spray volume savings of a prototype plant-specific sprayer are shown to be more than 75% in early late blight ( Phytophthora infestans ) control spraying in potatoes . In flower bulbs (lily ) it was shown that in Botrytis blight control on average spray volume could be reduced by 45%. In a potato crop biological efficacy was maintained at the same good level as of a conventional spraying. In a flower bulb crop biological efficacy of the CDS was lower than of conventional spraying, which means that spray strategy and dose algorithms need further research.

Driftreductie Munckhof MAS 3 rijen boomgaardspuit : effect van VARIMAS variabele luchtondersteuning en Randrijen instelling

Results of spray drift experiments are presented of the Munckhof MAS 3-row orchard sprayer in comparison with a reference spray technique for fruit crop spraying in The Netherlands. The Munckhof MAS 3-row orchard sprayer was equipped with a 90% drift reducing nozzle (Albuz TVI8001; 7 bar spray pressure), low level of air assistance (400 rpm PTO) and the VARIMAS variable air system and an Edge-Row setting. During the spray drift experiments the downwind outside 24 m of an apple orchard was sprayed at the full leaf stage (BBCH 91/92) using the fluorescent tracer Acid Yellow 250. Spray drift deposition was collected downwind of the sprayed orchard on a mowed grass area up to 25 m distance from the last tree row. Airborne spray drift was measured at 7.5 m distance from the last tree row on a pole at which two lines with collectors were attached at 1 m spacing up to 10 m height. The spray drift experiments showed that spraying an apple orchard at the full leaf stage (BBCH 91/92) with a Munckhof MAS 3-row orchard sprayer equipped with 90% drift reducing Albuz TVI8001 nozzles (7 bar), low level of air assistance (400 rpm PTO) and VARIMAS-system (last tree row sprayed from both sides) spray drift reduction at 4.5-5.5 m distance from the last tree row was 98.9% in comparison with the reference spray application. Using the VARIMAS-system with EdgeRow-setting the spray drift reduction was 99.5%. Airborne spray drift reduction at 7.5 m distance from the last tree row averaged over 10 m height was for the Munckhof MAS 3-row orchard sprayer equipped with 90% drift reducing Albuz TVI8001 nozzles (7 bar), low level of air assistance (400 rpm PTO) and VARIMAS-system 98.8% and for the VARIMAS-system with EdgeRow -setting 98.6%.