Day: October 17, 2022

Sensor Placement and Floating Row Cover Impact on Fruit Rotting Diseases in Strawberries

Scott D. Cosseboom and Mengjun Hu
Department of Plant Science and Landscape Architecture, University of Maryland College Park

Various sensors can be used to monitor environmental variables in fields, including ambient temperature, relative humidity, rain depth, wind speed, leaf wetness (LWD), soil temperature, and soil moisture. These can be critical variables for decision making for crop protection or yield prediction. These data (namely ambient temperature and LWD) can also be useful for disease prediction models such as those used for Botrytis (BFR) and anthracnose (AFR) fruit rots of strawberry (Hu et al. 2021). A traditionally placed weather station at the edge of a field (see ‘elevated’ station below) may also not fully capture the conditions in the field. Floating row covers are a common tool in Mid-Atlantic strawberry fields for manipulating the crop microclimate for facilitating crop development under cold conditions and for protecting from freeze events. Therefore, covered strawberry plants should have a vastly different microclimate than would be reported from traditionally placed weather stations or non-covered plants. We evaluated differences in sensor readings based on placements either in the canopy or in the traditional, elevated setting. We also evaluated the effect of row covers on the sensor readings. Lastly, we evaluated how these different placements would affect disease prediction models utilized in a fungicide spray program.

Continue reading Sensor Placement and Floating Row Cover Impact on Fruit Rotting Diseases in Strawberries

Emily Zobel, UME; ezobel@umd.edu & Jerry Brust, IPM Vegetable Specialist, UMD; jbrust@umd.edu

If you had plants in high tunnel this season that were showing drought and salt stress in the form of poor growth, thin canopy, excessive leaf drop, poor fruit set, poor yields, necrotic leaf margins, especially on older leaves that can curl, then you might want to consider testing your soil for high soluble salts. These excess soluble salts often come from compost, manure, or fertilizers frequently applied without sufficient water (rain) to leach them through the soil.  

High soluble salt levels in the soil can harm crops via drought stress in several ways. First, they can draw water away from plant roots resulting in wilted foliage and damaged roots (fig. 1). The plant roots can also absorb the excess soluble salts in the soil but cannot metabolize them. The soluble salts enter the roots and are moved through the water-conducting tubes to the leaves, where the water evapotranspires, gradually concentrating the salts to toxic levels. 

Some vegetable crops are much more sensitive to soluble salts than others. Crops such as green beans, onions, and peas are the most sensitive, while cabbage, cucumbers, peppers, and potatoes are a bit salt tolerant. Broccoli, squash, and tomato are moderately salt tolerant. 

Some possible remedies for high salts include having adequate drainage to help move salts out of the root zone and flushing the soil with as much water as possible for several days. When doing this, slowly apply the water, so it seeps into the soil and does not runoff. After the season, it may be best to take the plastic off the high tunnel and allow rain and snow to move the salts out of the growing zone, but you need to know if you have high soluble salt levels first, so it’s best to that soil test.