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Cheryl Trueman, Ridgetown Campus – University of Guelph; Janice LeBoeuf, OMAFRA, Ridgetown

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P1000636csBacterial spot, caused by a group of Xanthomonas bacteria, is an ongoing challenge for field tomato growers in Ontario. For many years, a program of fixed copper sprays was used to manage bacterial spot in plug transplants and field tomatoes. Transplant growers were advised to apply a fixed copper bactericide beginning 2 ½ weeks after seeding at 5-day intervals for a total of 5 applications. For field growers, the recommendation was to start to apply the copper within 7 days after transplanting — applying at least 3 applications at 7-day intervals. Knowing that copper and other products are relatively weak on bacterial disease, the strategy was to suppress populations early in the season while they are still low. Once symptoms are present, the bacterial populations are so high that we would not expect to have a significant impact on disease development with a spray program. Continue Reading »

There is a new blog in town.  OMAFRA’s fruit crop specialists recently launched ONfruit information for Ontario fruit growers.

In addition to a full suite of great information, you can also sign up to receive email updates whenever new content is added to the site.  Check it out.

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By: Kristen Obeid, OMAFRA Weed Management Program Lead – Horticulture and Clarence Swanton, University of Guelph

The Problem

Carrot growers in particular are struggling with resistant pigweed in Ontario fields, a problem that was studied extensively in 2011 and 2012. As far back as 1997, resistance to group 5 herbicides (prometryne) was noted. Then in 1998, resistance to group 2 (rimsulfuron) herbicides was noted. Resistance to group 7 (linuron) herbicides appeared in 1999. There are some weed populations with multiple resistance (i.e. resistance to both group 5 and group 7 herbicides or maybe even to three different herbicide groups).

Different pigweed species are showing resistance to herbicides, including:

  • Redroot pigweed (Amaranthus retroflexus, L.)
  • Green pigweed (Amaranthus powellii, S. Watson)
  • Smooth pigweed (Amaranthus hybridus, L.)
  • Common waterhemp (Amaranthus tuberculatus, syn, rudis)

Continue Reading »

J. Chaput, OMAFRA, Minor Use Coordinator, Guelph

The Pest Management Regulatory Agency (PMRA) recently announced the approval of URMULE registrations for SuccessTM and EntrustTM Insecticides for control of cabbage maggot on greenhouse broccoli transplants in Canada. SuccessTM and EntrustTM Insecticides were already labeled for use on many crops in Canada for a number of pests. Continue Reading »

Adapted from original article by J. Chaput, OMAFRA, Minor Use Coordinator, Guelph

The Pest Management Regulatory Agency (PMRA) recently announced the approval of several URMULE registrations for Coragen Insecticide for control/suppression of several Lepidopteran pests of  the green onion subgroup in Canada. Coragen Insecticide was already labeled for management of a number of insect pests on a wide variety of crops in Canada. Continue Reading »

2014 Vegetable Crop Protection GuideThe 2015 supplement to the OMAFRA Vegetable Crop Protection Guide (publication 838) is now available online. It provides information on new pest control product registrations and changes from November 2013 to November 2014.

PDF available online – EnglishFrench

From ONvegetables in The Grower, December 2014

Scientific Name: Certoma trifurcata

Identification
Bean leaf beetle adults are 5 mm in length with four black spots on the wing covers. A small, black triangle is visible at the base of the head (Figure 1, adult bean leaf beetle). The colour varies from yellow-to-tan or red. The black spots are not always apparent. Bean leaf beetle larvae complete their development in the soil, feeding on roots. The margins of the wing cover have a black border.

Damage starts as large holes in the leaves (Figure 2, bean leaf beetle feeding damage). As feeding continues, they consume the entire leaf expect for the veins, leaving a skeletonized appearance. Bean leaf beetle adults feed on leaves, blossoms and pods.

bean leaf beetle adult

Figure 1. Adult Bean Leaf Beetle

bean leaf beetle feeding injury

Figure 2. Bean Leaf Beetle Feeding Damage

Biology
Bean leaf beetles over-winter as adults in grassy fencerows, leaf litter and wooded areas. They emerge in late-April and may be found feeding in alfalfa fields. Early snap bean fields planted close to alfalfa are at the greatest risk of bean leaf beetle damage.

The over-wintering female beetles lay clusters of lemon-shaped, bright orange eggs at the base of the bean plant. Egg-laying continues until late June. Larvae feed on roots and soil debris for approximately 30 days prior to pupating. First generation adults emerge in mid-to-late-July. This generation lives for approximately 1 month. A second generation of adults emerges mid-to-late August and feeds until it runs out of a food source, either due to harvest activities, crop senescence or cold fall temperatures, and the adults migrate to their over-wintering sites.

Period of Activity
Generational peaks occur from crop emergence to late-June (overwintering), mid-to-late July (first generation) and late-August (second generation).

Scouting Notes
These pests often feed in clusters. Examine 1m of row at each of 10 locations across the field. Select a wide range of field locations, including border areas.

Thresholds
Apply a control if beetles exceed 1 beetle per foot of row or if defoliation exceeds 25%. Defoliation prior to bloom does not have as strong an impact on yield. Early season bean leaf beetle populations may be adequately controlled by systemic insecticide seed treatments used to control potato leafhopper.

Tolerances in snap beans will be significantly lower after pod-set if the beetles are feeding on the pods or where they may become potential contaminants for the processor.

Management Notes
Consider using border sprays to control the beetles as they move out of the fencerow. Consult the Ontario Vegetable Crop Protection Guide (OMAFRA publication 838) for a list of registered foliar and seed treatments.

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