Tag Archives: bacterial disease

Ontario Fruit and Vegetable Convention presentations now available online

Ontario Fruit & Vegetable ConventionPresentation slides from the 2017 Ontario Fruit and Vegetable Convention (OFVC) are now posted online. Field vegetable content at this year’s OFVC included: Continue reading Ontario Fruit and Vegetable Convention presentations now available online

66th Annual Muck Vegetable Growers Conference

The 66th Annual Muck Vegetable Growers Conference will be held April 12-13 at the Bradford and District Memorial Community located at 125 Simcoe St., Bradford, ON. The conference is free and registration starts at 8:30. For more details please see:  http://www.uoguelph.ca/muckcrop/muckconference.html

Continue reading 66th Annual Muck Vegetable Growers Conference

Managing Bacterial Spot in Ontario Field Tomato Production

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

Bacterial spot on tomato plant and fruitBacterial 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. 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 Managing Bacterial Spot in Ontario Field Tomato Production

New data shows need for an integrated approach to bacterial spot management in Ontario tomato production

Cheryl Trueman, College Professor, Ridgetown Campus, University of Guelph

Producers of transplants for field production of fresh market and processing tomatoes typically use regular applications of copper hydroxide (Kocide 2000 or Coppercide WP) to manage bacterial diseases during greenhouse production. The efficacy of this standard practice and other potential new management tools for bacterial spot (Xanthomonas gardneri) were recently evaluated at Ridgetown Campus, University of Guelph.

What we did:

  • Each plot consisted of tomato seedlings (cultivar TSH32) growing in one half of a 200-cell tray (approximately 100 plants). Plots were separated by barriers 40 cm in height to prevent interference from neighbouring trays (Figure 1).
  • Product application descriptions are summarized in Table 1. Products tested included:
    • Kocide 2000 (copper hydroxide 53.8%)
    • KleenGrow (didecyl dimethyl ammonium chloride 7.5%)
    • Actigard (acibenzolar-S-methyl 50%)
    • Actinovate (Streptomyces lydicus strain WYEC 108 1 x 107 cfu/g)
    • AEF 1301 (unknown)
    • Cyclone (lactic acid 10.73 g/L, citric acid 21.37 g/L; present as fermentation products of Lactobacillus casei strain LPT-111)
    • Zerotol (hydrogen peroxide 27%).
  • Trays were inoculated by replacing one healthy seedling at the center of each tray with one seedling inoculated with a copper-sensitive strain of Xanthomonas gardneri and showing symptoms of bacterial spot.
  • The area of the tray with bacterial spot symptoms was monitored over time.

Continue reading New data shows need for an integrated approach to bacterial spot management in Ontario tomato production

Watch for Increased Insect Activity in Sweet Corn and Pumpkins

By: Elaine Roddy, Vegetable Crops Specialist
OMAFRA – Ridgetown

In general, insect pressure has been relatively low this year.  However, over the past week we have noticed an increase in insect activity.

Sweet Corn
Start scouting for European corn borer at the mid-whorl stage, before the tassel begins to emerge from the plant.  Look for flattened, white egg masses on the under surface of the leaves. Newly hatched larvae often hide in the developing tassel during the heat of the day.  Window panes, pin-hole feeding and small amounts of saw dust-like frass are all signs of feeding. Optimal control occurs during the early stages of insect development, before the larvae enter the stalk. Young larvae range in colour from almost translucent to yellow to brownish, with a black head.

The website, insectforecast.com reports scattered flights of corn earworm into the great lakes region. Corn is susceptible to earworm infestation during the silking period. The best way to monitor for the presence of corn earworm is with a pheremone trap. Continue reading Watch for Increased Insect Activity in Sweet Corn and Pumpkins

Seed Disinfestation Strategies for Saved Pumpkin and Squash Seed

by Elaine Roddy, OMAFRA and Cheryl Trueman, University of Guelph – Ridgetown Campus

Seed borne diseases represent a real threat to pumpkin and squash production. Commercial seed is typically grown under arid conditions, and is carefully monitored to ensure it is disease-free. It is difficult to employ those precautions to saved seed produced on the farm here in Ontario.

A new disease that is cause for considerable concern is bacterial leaf spot (Xanthomonas cucurbitae). While it has only been identified in 2 locations in Ontario (Kent County in 2012 and Elgin County in 2014), experience in the mid-western US has shown that field infestation levels of 60-80% are not uncommon.

In 2014, we investigated methods of on-farm seed treatment to disinfest saved-seed. Both the hot water treatment and the chlorine treatment effectively killed the bacteria present on the batches of seed infested with X. cucurbitae.[1] There was a 5% reduction in germination of the chlorine-treated compared to untreated seed. Germination rates in the hot-water treated seed were similar to those in the untreated seed.

The methodology used in the 2014 study is outlined below.  **Note: test a small batch of seed for each cultivar to be treated. The 2014 study was conducted on Waltham butternut squash. Other varieties or types of cucurbits could potentially be more sensitive to either the chlorine or hot water treatments. In particular, other researchers have reported negative effects of hot water treatment on cucurbit seedling emergence (Miller and Ivey, 2005). Continue reading Seed Disinfestation Strategies for Saved Pumpkin and Squash Seed