By: Sean Westerveld, OMAFRA and Amy Fang Shi, OGGA
At this time of year, many unusual symptoms can show up in specialty crop fields. If a disease is suspected, samples can be sent to diagnostic labs for determining the cause. However, diagnostic reports are not always designed for growers to interpret, which can often lead to misunderstanding as to the potential causes of the symptoms. It is important to understand the limitations of diagnostic tests so unnecessary control measures are avoided.
Lavender bloom is nearly complete for another year. Growers with distillation equipment are likely busy distilling now and over the next few weeks. Otherwise, pruning can be done anytime between now and the end of August. Fertilization can continue to about mid-August. Planting new plants can be done in the summer as well but requires extra care. Here some notes on each of these tasks:
Other than the normal lingering Phytophthora root rot issues and occasional Alternaria escapes, few pest issues have been reported over the past few weeks. Except for some severe spring storms, weather conditions have been ideal for ginseng production up to this point with mostly dry weather and normal temperatures. Although temperatures have occasionally been hot, there have also been plenty of cooler days and nights to reduce plant stress. Temperatures are forecast to be above normal beginning this weekend, which could increase plant stress. Along with longer dew periods at this time of year, this could increase Alternaria disease pressures. Although most areas received a much-needed rain early last week, rainfall since then has been more sporadic. It is important to monitor soil moisture closely and ensure timely irrigation to reduce plant stress and the risk of Alternaria outbreaks.
Lavandula angustifolia cultivars are past peak in most areas and L. x intermedia (lavandin) cultivars are beginning to bloom. Harvest for essential oil can begin at any time for angustifolia cultivars and harvest for bundles and buds has begun in warmer regions for lavandins.
The biggest pest issues at this time of year are garden fleahoppers and Japanese beetles. Garden fleahoppers usually hide within the canopy and scrape the leaves causing them to turn silvery. Shaking the plant vigorously above a white sheet of paper will make them visible. Look for tiny green nymphs and black adults that jump easily when disturbed. If populations are high, they can stunt the plants and prevent regrowth after bloom. This appears to be more likely over black plastic. Insecticidal soaps registered for aphid control may suppress garden fleahopper populations.
Much of the ginseng-production area has received little to no rain over the past month. Combined with average temperatures and lower humidity, this has kept disease pressures, especially Alternaria and Phytophthora, lower than normal except in areas with lingering root disease from last fall. No major insect issues are being reported.
By: Rebecca Shortt, Water Quantity Engineer, OMAFRA
It has been hot and dry in SW Ontario in June.
What is the impact on plants? And how do we measure the water demand?
One thing I think we forget is that those days of high humidity are not as hard on the plants as days with low humidity which are very desiccating (however the humidity is hard on us humans!).
www.Farmwest.com uses Environment Canada weather data at a selection of Ontario weather stations to calculate the daily Evapotranspiration (ET). This is a measure of how much water a mature grass cover crop would use if it had ample water available.