Carrot weevil remains the most important insect pest to many Ontario carrot growers, and the amount of damage seems to be increasing in recent years. Carrot weevil females overwinter in the soil and plant debris and lay their eggs in cavities in the crown of the carrots. These eggs develop and hatch into larvae and begin to feed on the carrot root. Feeding damage from the carrot weevil larvae causes unmarketable tunneling near the crown of the carrot and can account for significant losses to commercial growers.
Kristen Obeid, OMAFRA Weed Specialist – Horticulture
Flea beetles are a common crop pest of crucifers in Ontario and overwinter as adults near the soil surface in debris and stubble from the previous crop. They typically become active with the first extended period of warm weather in the early spring as the leaf litter begins to thaw. The beetles feed on weeds throughout the field and have the ability to fly on calm days and will attack brassica seedlings as they emerge or transplants as they are planted.
Females will begin laying eggs in soil for about 30 days. Flea beetle larvae will hatch from eggs 12 days later and feed on the root hairs and taproots of seedlings. Left unchecked, adults will feed on leaves of transplants and the larvae will burrowing into the plant near the juncture of the root and stem. Continue reading Preventing Yield Loss from Flea Beetles
Originally published in ONvegetables in The Grower, April 2017
Even with the use of herbicides, broadleaf weed control in pumpkins and squash can be problematic. Product selection is key but timing and weather conditions are also important to the success or failure of a weed control program. Each of the broadleaf herbicides comes with its own strengths, weaknesses and risks.
As a general rule, the spectrum of weeds controlled can be increased by using tank-mixes. But, for pumpkins and squash, it is wise to limit the tank-mix to two products. A three-way tank mix is risky from a crop safety standpoint; root damage, stunting, yellowing and/or burning may occur, especially under certain soil conditions.
All of the pre-emergence herbicides require soil moisture. The active ingredient is carried by the soil water into the germinating weed seedlings, causing them to die. Under dry soil conditions, it is tempting to use overhead irrigation to “activate” the herbicides. This is an inexact science. Too much water can quickly move the herbicide band into the zone of the germinating crop roots, causing injury to the pumpkins or squash. Too little water may be insufficient to move the herbicide into the germinating weeds.
It becomes a gamble between loosing crop to herbicide damage or loosing yield to weed competition. Fortunately, both Dual II Magnum and Sandea can be used for early post emergence weed control. Unfortunately, control of weeds such as lamb’s-quarters and pigweed is less effective with a post emergence spray.
Product: Command 360 ME (clomazone)
Timing: after seeding but before crop and weed emergence.
Rate: 0.78-1.17 L/ha (0.31-0.47 L/acre) use the low rate on light, sandy loam soils; use the high rate on heavy soils.
Strengths: lamb’s-quarters, nightshades, ragweed, velvetleaf
Cautions: very sandy soils and/or certain varieties may be prone to crop injury, see label for details. Also refer to the label for rotational crop restrictions.
Product: Sandea (halosulfuron)
Timing(s): after planting and before soil cracking (direct seeded), before transplanting; do not transplant sooner than 7-days after application, OR post-emergence between the 3-5 true leaf stage or 14-days after transplanting
Rate: 35-70 g/ha (14-28 g/acre). See the product label for specific rate information for direct seeded, transplanted, processing and fresh market pumpkins and squash.
Strengths: pigweeds, lady’s thumb, mustards
Cautions: Under adverse growing conditions (dry or excessive moisture, cool weather, etc.) the maturity of the treated crop may be delayed which can influence harvest date, yield, and quality. Under dry soil conditions, apply 3 – 5 cm of sprinkler irrigation to settle the soil after planting and prior to application. Do not make a post emergence application if female blossoms are present on the plant; crop damage may occur to developing fruit.
 If using pre-emergence and post emergence applications of Sandea, allow for a minimum of 21 days between the two applications.
Product: Dual II Magnum (s-metolachlor/benxacor)
Timing: pre-emergence or at the 1-2 leaf stage (direct seeded crops). Prior to transplanting or within 48 hours after transplanting (transplanted crops).
Rate: 1.15 L/ha (0.47 L/acre)
Strengths: annual grasses, nightshades, pigweeds
Weaknesses: lady’s-thumb, ragweed, velvetleaf
Cautions: risk of crop injury increases with cool and wet conditions. Foliar contact can increase the potential of crop injury. Note: research in Ontario has shown high levels of phytotoxicity when using Dual II Magnum on cucumber crops. Use on cucumber crops is not recommended.
Jim Chaput, Minor Use Coordinator
The Pest Management Regulatory Agency (PMRA) recently announced the approval of an URMULE registration for Prowl® H2O Herbicide for control of labeled weeds on direct seeded, green (bunching) onions grown on muck soil in eastern Canada and British Columbia. Prowl® H2O Herbicide was already labeled for use on a number of crops in Canada for control of weeds. Continue reading Prowl® H2O Herbicide label expanded for control of labeled weeds on direct seeded green onions grown on muck soil
PMRA has completed a special review on Paraquat (Gramoxone Liquid Herbicide) and proposed a phase-out of the product. See part of the decision below: Continue reading Gramoxone Phase-out, Safe Use and Stewardship Changes
This is one to review and share! A very educational slide show from Jason at Sprayers101.com
There’s been unprecedented demand for information regarding the safe and effective application of the new dicmaba products registered in Canada in late 2016. In response, every extension agent, agrichemical rep and researcher with any know-how on the subject has spent the last year (or more) speaking at grower meetings. I, for one, am fairly certain…