A Longer Strawberry Season in Canada Would Require More Fungicide Sprays

Anthracnose fruit rot

Anthracnose fruit rot

Ripening strawberries are very susceptible to anthracnose. The pathogen spreads rapidly through fruiting fields during rainy, warm harvest seasons and can quickly destroy a crop. Light-brown water-soaked spots form on ripening fruit and rapidly develop into firm round lesions followed by the eruption of pink spore masses in a slimy sticky matrix which are dispersed by splashing or wind-driven rain.

“In Canada, strawberry is cultivated mainly in Quebec, Ontario, British Columbia and the Atlantic provinces. Ontario ranks as the second highest strawberry producer (30%) in the country, with a farm-gate value of Cdn$ 20.8 million. Most of the fruit produced in Canada are from June-bearing cultivars, with a season that usually spans 5-6 weeks in June and July. In the off-season, large quantities of strawberries are imported, which were five times higher in 2011 than in 2003. The Canadian strawberry industry has given high priority to cultivation of day-neutral strawberry to become more competitive with the import market and increase the availability of fresh Canadian-grown strawberries to 4-5 months.

Anthracnose fruit rot (AFR), caused by Colletotrichum acutatum Simmonds, is one of the major diseases affecting yield in Ontario and other provinces. Pre- and post-harvest fruit rots caused by the fungus reduce marketable yields and the marketability of fruit, respectively. Long wet periods and warm temperatures (20-25 °C) during flowering and fruit development are favourable conditions for development of anthracnose fruit rot.

With the increase in production of day-neutral cultivars in Canada, attention should be given to the differences in cultivation practices from June-bearing cultivars. Since day-neutral strawberry have a longer cycle of fruit production, the risk of diseases and pests is also higher and thus different management strategies are required.

Since the day-neutral cultivars can be grown for a long season (4-5 months), numerous sprays (8-10) of fungicides are required to control diseases.”

Authors: Burlakoti, R. R., et al.
Affiliation: Weather Innovations Consulting LP.
Title: Evaluation of epidemics and weather-based fungicide application programmes in controlling anthracnose fruit rot of day-neutral strawberry in outdoor field and protected cultivation systems.
Source: Canadian Journal of Plant Pathology. 2014. 36[1]:64-72.

No Apple Maggots in Northwest Orchards Thanks to Spraying Outside the Orchards


Apple Maggots

Apple maggot is a native pest of the eastern United States and Canada. In 1979 it was discovered in Oregon and has since moved into California, Washington, and other Western states. Female apple maggot adults deposit eggs singly under the apple skin. Damage is caused when larvae burrow and feed on apple flesh. Browning of the trails occurs as the apple responds to this injury and bacteria associated with maggots cause fruits to rot internally. No Western commercial apples have been infested with maggots thanks to spraying trees outside the orchards to keep them away.

“The first detection of this species [apple maggot] infesting apples in western North America occurred in the United States in Oregon in 1979; flies were caught in neighboring Washington the following year. However, no commercial apples from central Washington, the major apple growing region in the United States, have been found to be infested by R. pomonella, even though adults were first detected within this region in 1995.  

In Washington, an R. pomonella quarantine is established in 22 counties, including two under partial quarantine.

R. pomonella is widespread and abundant in Washington west of the Cascade Mountain range, but is much less abundant in central and eastern Washington except in Spokane County. It occurs in low numbers on the margins of the apple-growing regions in central Washington in native hawthorns and in even lower numbers in unmanaged roadside and backyard apples.

…In the major apple-producing regions of the Pacific Northwest of the United States, control does not occur at the orchard level but rather outside orchards. There is zero tolerance for infested apples. The probability of R. pomonella being moved in apples from Washington to Canada or Mexico is minimized by an extensive annual fly detection and insecticide spray response program conducted by the WSDA and cooperating county pest control boards. …Similar programs exist in Oregon, Idaho, and California.”

Authors: Yee, W. L., et al.
Affiliation: Agricultural Research Service, United States Department of Agriculture
Title: Status of Rhagoletis (Diptera: Tephritidae) Pests in the NAPPO Countries.
Source: J. Econ. Entomol. 2014. 107[1]:11-28.

Canadian Onions for Long-Term Storage Depend on Fungicide Sprays

Late Blight Caused By Botrytis

Late Blight Caused By Botrytis

In eastern Canada, Botrytis Leaf Blight (BLB) of onions caused by the fungus Botrytis squamosa is the key disease for scheduling fungicide applications. BLB is characterized by silver halos on green leaves, followed by leaf tip dieback and leaf blighting, which reduces photosynthesis and consequently bulb size. Although there are some onion cultivars that are tolerant to the disease, they are not widely-planted in Canada because they are not suitable for long-term storage.

“There are no commercially available onion cultivars that are resistant to B. squamosa. However, a few of the early cultivars are known to be tolerant. These cultivars can produce a marketable yield under wet weather conditions and are grown on both conventional farms and organic certified farms for which there are no registered fungicides that are effective against BLB. However, these cultivars are not suitable for long-term storage; hence, they represent only a small part of the total onion acreage in northern climates. Consequently, in most onion production areas where BLB is a problem, the disease is managed through repeated applications of fungicides on a regular calendar-based schedule or following a leaf blight predictive system. Typical fungicide spray programs involve applying fungicides every seven to ten days from the four-leaf growth stage until sprout inhibitor application or 50% soft neck stage.”

Author: Herve Van der Heyden, et al
Affiliation: Compagnie de recherché Phytodata Inc. Quebec, Canada
Title: Comparison of monitoring based indicators for initiating fungicide spray programs to control Botrytis leaf blight of onion
Source: Crop Protection. March 2012. 33:21-28.

Southern California Vineyards Recover Thanks to Insecticide Applications

Grapevines Destroyed in 1999

Grapevines Destroyed in 1999

Temecula Today

Temecula Today

In 1999, about one-third of the vineyards in Temecula Valley, Riverside County, California were destroyed due to Pierce’s Disease which is caused by a bacteria transmitted to grapevines by an insect-the glassy winged sharpshooter. The disease seemed destined to spread throughout Southern California. However, research demonstrated that a carefully-timed insecticide application would prevent the sharpshooter from transmitting the disease to grapevines. As a result of this insecticide use, the wine grape industry in Southern California has recovered and is prospering.

“Twelve years ago a Pierce’s disease epidemic in Southern California wine grapes prompted a multi-pronged local, state and federal attack to contain the disease spread and find a cure or treatment.

Riverside County agriculture officials declared a local emergency in 1999 and 300 acres of Temecula wine grape vines were destroyed after they were found to be infested with the glassy winged sharpshooter.

Emergencies were declared, a task force was formed, and in 2000 $22.3 million in federal financial assistance was secured to reduce pest infestations and support research.

Research found that the Southern California epidemics were almost entirely the result of vine-to-vine transmission…. A protocol of applying one carefully timed application of a persistent systemic insecticide such as imidacloprid virtually eliminates the vine-to-vine spread.

Ben Drake is a Temecula-area wine grape grower and vineyard manager who began seeing problems from PD in the Temecula Valley as early as 1997.

We’ve found that if we apply (imidacloprid) at the middle to the end of May, before the sharpshooter moves out of the citrus and goes into the vineyards, we get levels of the material into the plant high enough that when the sharpshooter flies over from the citrus groves to try it, they just fly back where they came from. Or, if they feed long enough, it will kill them.

But just look at the Temecula Valley now to understand what’s changed: From 12 wineries in 1999, the Temecula Valley Winegrowers Association website today lists more than 50 growers and 34 wineries…. A thriving agritourism industry has developed…. Existing wineries are expanding and new ones are under construction or in planning phases.”

Author: Christine Thompson
Affiliation: Reporter
Title: Grape growers urged to remain vigilant against sharpshooter pest
Source: Western Farm Press. 2011-12-12. Available at: http://westernfarmpress.com/grapes/grape-growers-urged-remain-vigilant-against-sharpshooter-pest

Onion Plants Die Without Insecticide Treatments

Onion Maggot Damage

Onion Maggot Damage

100,000-300,000 onion maggots overwinter on every acre of onions in northern states. The average number of eggs laid by a single female in the spring is about 50. The emerging maggots seek out the roots and bulbs of onions and tunnel into the bulb. Maggots feed for two to three weeks. Damaged plants are usually so severely injured that they wilt, dry out and soon disappear.

“Management of onion maggot Delia antiqua is an integral component of onion production in the northern United States and Canada. There are three generations of D. antiqua per year in the northern United States and infestations of first-generation D. antiqua typically cause the most serious damage because maggot feeding kills seedlings. If onion seedlings are not protected with an insecticide applied during planting, D. antiqua can reduce plant stands by one-half to near 100%.”

Authors: B. Nault, J.Z. Zhao, R. Straub, J. Nyrop and M.L. Hessney.
Affiliation:  Department of Entomology, NYSAES, Cornell University.
Title: Onion Maggot (Diptera: Anthomyiidae) Resistance to Chlorpyrifos in New York Onion Fields.
Publication: Journal of Economic Entomology. 2006. 99(4):1375-1380.

30 Years Ago, We Knew Herbicides Increased Canadian Wheat Yields

Canada ranks sixth in the world in wheat production and is the second largest exporter of wheat with 70% of its production exported annually. Since 1960, wheat yields have doubled in Canada. A group of Canadian researchers set out to identify the key factors accounting for the yield increase…

From abstract: “Therefore, we suggest that chemical weed control was the main contributing factor to the yield increases. This control has resulted not only in reduced competition from weeds, but also in better seedbed moisture because fewer cultivations are needed in the spring. “

“Because of the ability to control weeds with chemicals, it is now also possible to seed shallowly into a moist seedbed immediately after one cultivation since numerous spring cultivations with a resultant loss of valuable soil moisture are no longer necessary to eliminate germinating seeds. Fertilizer application and improved cultivars have also contributed, but to a lesser degree, to the yield increases.”

Authors: S. Freyman et al.
Affiliation: Agriculture Canada, Lethbridge, Alberta, Canada
Title: Yield trends on long-term dryland wheat rotations at Lethbridge.
Publication: Canadian Journal of Plant Science. (1981) 61:609-619.

Fungicides are Key to Canada’s Large Chickpea Crop

Chickpea is among the newest crops in West Canada, where it has been produced in sizeable quantity since 1997. Canada is now a competitive producer, processor and exporter of chickpeas, with exports valued at $50 million per year. Fungal diseases pose the most important constraints on chickpea production in Canada – ascochyta blight is the most problematic. Fungal infections cause initially small whitish spots that enlarge to become tan colored as the cells in the leaves die. Stem infections are considered very damaging as they often cause stem breakage, thereby destroying healthy branches.

“Ascochyta blight of chickpea has been a major biotic constraint to chickpea production in Saskatchewan where the vast majority of Canadian chickpea is grown. Under conditions conducive for disease development, yield losses of close to 100% have been encountered in the Canadian prairies. … Host plant resistance to the pathogen is partial and plants become increasingly more susceptible with the initiation of flowering. Major resistance breakdown due to genetic changes in pathogen populations has been observed in Saskatchewan.”

“The timely and efficient use of fungicides has remained a major factor in the successful management of the disease and the economic viability of the crop.”

Authors: S. Banniza¹, C.L. Armtrong-Cho¹, Y. Gan² and G. Chongo¹.
Affiliation: ¹Crop Development Centre, University of Saskatchewan; ²Agriculture and Agri-Food Canada, Saskatchewan
Title: Evaluation of fungicide efficacy and application frequency for the control of ascochyta blight in chickpea.
Publication: Canadian Journal of Plant Pathology. (2011) 33(2):135-149.

North American Ginseng Production Depends on Fumigation

Roots of American ginseng are common ingredients in herbal medicines. However, being a root crop subjects ginseng to attacks by soil-dwelling organisms, which cause root rot of ginseng seedlings. In order to prevent damage to the roots, growers typically fumigate fields before the ginseng crop is planted.

“An important component of many traditional Asian herbal medicines is dried root of American ginseng (Panax quinquefolius L.). … Although indigenous to the forests of eastern North America, most of the world supply of dried root is now provided by crops grown in cultivated fields under artificial shade structures. Over two-thirds of Canada’s ginseng crop is grown in the sandy soils of southwestern Ontario.”

“Current production methods provide environments favourable to disease development, and crop loss due to disease is significant. Although ginseng germplasm is diverse, disease-resistant cultivars are not available. … To reduce risk of damage from soilborne species of Pythium and nematodes, ginseng growers normally fumigate fields prior to seeding.” 

Authors: R.D. Reeleder¹, J. Miller¹, B. Capell¹ and J. Schooley²
Affiliation: ¹Agriculture and Agri-Food Canada, Ontario, Canada; ²Ontario Ministry of Agriculture, Ontario, Canada.
Title: Mefenoxan sensitivity and the impact of fumigation on Pythium species and Phytophthora cactorum in ginseng soils.
Publication: Canadian Journal of Plant Pathology. (2007) 29:427-436.