High moisture conditions this year are likely to result in more disease pressure.

“The scouting time would be right around early flowering and some fields have started to flower already,” said Dennis Lange, provincial pulse specialist.

According to Manitoba Pulse and Soybean Growers, “mycosphaerella blight is the most widespread and economically damaging foliar disease of field peas in Manitoba.”

WATCH THIS: Dennis Lange discusses spray-timing a fungicide for mycosphaerella blight in peas.

It only affects peas and can be controlled by foliar fungicide. Most pea crops are infected with the disease every year. The earlier the infection sets in and the quicker it moves up into the canopy, the greater the effect on yield.

“The thing you’re looking for in the lower canopy is those purple freckles,” Lange said. “And sometimes you have to kind of spread the canopy back to really have a closer look.”

Lange notes that mycosphaerella is easy to mistake for bacterial blight, particularly if there’s been hail damage.

“Usually that’s what ends up happening when you have some severe weather that goes through,” Lange said.

However, there are a few distinguishing factors to identify both mycosphaerella and bacterial blight.

“One of the first things with mycosphaerella, it’s more about purpling discolouration like purple freckles, where bacteria is more yellow, yellow or brown, sometimes you see a bit of a yellowish ring around it,” he said.

“The other distinguishing factor is that with bacterial blight, the lesion generally stays within the veins. It doesn’t go across the veins as the disease develops.”

Also, bacterial blight is likely to be more widespread, “especially given the weather we’ve had,” Lange said.

Even with last year’s dry conditions, mycosphaerella spores can survive. Lange described an experiment at the Crop Diagnostic School earlier this month in which straw from last year’s pea field was put into the plots to see if there would be more infection. There was.

“That just tells us that even in a dry year, the mycosphaerella is there,” Lange said.

He encourages growers to use the mycosphaerella checklist to determine the extent of infection. It also offers a rating scale to determine when to spray.

“Ideally, you want to be at least 65 before you spray,” Lange said. “The reason we do that is so that when we’re targeting spray application, we want to target the best timing.”

Every field is going to have mycophaerella at some point in the growing season, he said, but fungicide shouldn’t be applied until infection levels reach the threshold. Then the application is more likely to last long enough to control the infection for the long-haul. If applied too early, the infection could return when the effect of the fungicide wears off.

“You want the spray to be late enough to carry it through to early pod-fill,” Lange said.

The post Scout early for blight in peas appeared first on Manitoba Co-operator.

Cereal leaf beetle and thrips are noticeable in some fields of small grain cereals, but at below economical levels. Initial tests of levels of parasitism of cereal leaf beetle larvae show quite high levels in the Central region, with samples from other regions soon to be tested. Thanks to those agronomists who have provided field locations, or collected and sent in samples of cereal leaf beetle larvae to be tested for parasitism. See last weeks update for details on collecting and submitting cereal leaf beetle samples to determine level of parasitism.

Low levels of thistle caterpillars have been noted. Although these will feed on sunflowers, the level of feeding is not normally economical, and they can do a lot of feeding to thistles.

Bacterial blight in oats has been detected in the Red River Valley. As temperatures increase plants will typically grow out of the symptoms.

Loose smut has been detected in a wheat field near Niverville.

Phytophthora root rot (PRR) in soybean has been reported in the Red River Valley. This disease thrives under wet conditions and can cause yield loss depending on incidence. Typically PRR affected plants will prematurely senesce and not set seed.

Bacterial Blight in Oats

Bacterial blight in oats has been reported in various areas of the Red River Valley. This disease thrives under cool and moist conditions. Typical symptoms symptoms include water soaked areas that eventually turn necrotic. The affected areas often form longitudinal blotches or stripes. As temperatures warm up the plants are able to grow out of the symptoms. Yield loss is not generally a concern with this disease.

Loose Smut in Wheat

There has been a report of smut in wheat from the Niverville area. This disease is also favoured by cool humid/wet conditions. Smut is typically managed through using resistant varieties and seed treatments. The variety where symptoms were observed is Carberry. Symptoms of smut typically show up at the same time as head emergence. In the affected field, incidence was low overall with scattered plants showing up across the field.

Phytophthora Root Rot in Soybean

There have been multiple reports of Phytophthora root rot (PRR) in soybean in the Red River Valley. In at least one case, the incidence is reported as up to 30 per cent of plants affected. PRR is caused by an oomycete and thrives under water logged conditions. Symptoms can show up in patches in the field (low spots) or as scattered plants. Severely infected plants will completely senesce, but the leaves will stay attached. PRR is common in areas of the province that have had a history of soybean production and in years where there are water-logged conditions.

Scouting for thrips in barley

Barley thrips can at times get to economic levels in barley, but populations can be quite variable between and within fields. What should be monitored is levels when the flag leaves are first visible until the heads are completely emerged from the boot.

Economic thresholds have been established; the threshold (thrips/stem) = (Cost of control / expected dollar value per bushel)/ 0.4.

This often works out to around 4 adults per stem, but because the value of barley can vary greatly depending on use and market, it is good to use this simple formula to determine the economics of potential management. Insecticides are only going to provide value if applied before heading is complete, if levels of thrips are high. Also note that barley thrips may be more numerous near protected field margins than other areas of the field.

Agronomists, Farmers, Farm Production Extension Specialists, Extension coordinators, and others scouting crops: Please remember to send in reports of insects or plant diseases over the growing season so we can make these updates as complete as possible, and alert farmers and agronomists where and to what degree insects and pathogens are of concern or being controlled. Information can be sent to: John Gavloski (entomologist) at John.Gavloski@gov.mb.ca (phone: 204-750-0594) or Holly Derksen (plant pathologist) at Holly.Derksen@gov.mb.ca (phone: 204-750-4248).

Visit the insect pages on the Manitoba Agriculture website at www.gov.mb.ca.

Click here to view the complete Manitoba Insect & Disease Update on the Manitoba Agriculture website.

The post Alfalfa weevil still at high levels, root rot in soybeans reported appeared first on Manitoba Co-operator.

Potato leafroll virus

Potato leafroll virus can cause foliar symptoms of disease, one of which, as the name implies, causes the leaves of the potato plant to roll. It can also cause the leaves to become pale and chlorotic. Symptoms of infected tubers can include internal net necrosis, as well as reduced tuber size and overall yield. Some varieties are more susceptible than others and some varieties may be infected without expressing symptoms.

The primary means of spreading potato leafroll virus from plant to plant during the season is by aphid feeding. Overwintering and infection from one season to the next is commonly achieved in live plant tissue such as infected potato tubers. Potato leafroll is managed by a combination of planting seed tubers free of leafroll virus, eliminating volunteer potatoes and weeds, eliminating refuse tubers and managing aphids.

Potato virus Y

Potato plants infected with potato virus Y may show a wide range in severity of symptoms depending upon the potato variety. The range may include infection with no symptoms, mild foliar mosaic symptoms or severe symptoms such as wilting of the entire plant and death. Certain strains of potato virus Y, such as PVYN (the “n” stands for necrotic), can cause necrotic symptoms in tubers. Red Norland and Russet Burbank are two examples of particularly sensitive varieties. Some varieties, such as Russet Norkotah, may carry potato leafroll virus without expressing symptoms and are still capable of transmitting the disease.

• Read more: Dicamba drift a new danger for potato growers
• Read more: Fumigation a potential solution for ‘tired potato land’

As with potato leafroll virus, aphids are the primary means in which the disease is spread from plant to plant. Infected potato tubers (seed potatoes and volunteers) are the primary source for new infections in the following season. Planting resistant varieties like the Premier Russet can help reduce the incidence of infection and rate of transfer while growing and yielding normally despite infection.

For more information on potato virus Y, see the USDA’s Managing Potato Virus Y in Seed Potato Production website.

Late blight (Phytophthora infestans)

Late blight is perhaps the most famous of the potato diseases. Many U.S. citizens of Irish descent can trace their roots back to ancestors who emigrated from Ireland in the 19th century to avoid famine due to consecutive failed potato crops due to late blight. Late blight is a fungal disease that overwinters on live plant tissue and can cause severe destruction to the foliage of potatoes and tomatoes. It is spread by fungal spores that can move on air currents or mechanically.

Like the viral diseases mentioned above, infected seed potatoes and volunteers are often a means of overwintering from season to season. To get details on the late blight risk level in your area, visit Michigan State University’s Late Blight Risk Forecasting website.

Disease free

All three of these diseases are commonly carried from one growing season to the next in potato tubers. Michigan State University Extension recommends planting disease-free seed potatoes as an important step in breaking the disease cycle and preventing the disease from becoming established. While it may be tempting to save a few potatoes from your favourite varieties to plant each year, or purchase seed from an uncertified source, purchasing professionally grown, clean seed will pay long-term dividends. For all growers, both large and small, one infected seed lot has the ability to spread disease from plant to plant as well as field to field and farm to farm.

The post Plant clean seed potatoes appeared first on Manitoba Co-operator.

The key is managing for the fungal disease before it becomes a serious problem.

The precautions to take range from choosing tomato varieties resistant to late blight, to knowing how to spot the disease’s first signs and notifying neighbours and authorities right away, says farm production extension pathologist Vikram Bisht.

Late blight was first detected in a potato field near Carberry July 16 last year and by early August more than a dozen fields in the area were infected. Had commercial potato growers not applied fungicides to protect their crops, it’s estimated anywhere from 75 to 80 per cent of this province’s potato crop could have been infected too.

The same fungus is a source of infection for both tomatoes and potatoes. Home gardeners certainly lost their crops last year, but it was market gardeners who were hit especially hard as the disease spread.

“The fungus we had last year, or the strain, was extremely virulent or aggressive on tomatoes,” said Bisht.

The pattern of infection in Manitoba shows late blight is spread by the fungus’s spores travelling by wind during intense thunderstorms. It tends to show up on the west side of the province and then within five or six weeks has travelled easterly across Manitoba.

To avoid its spread, the most important thing growers of both tomatoes and potatoes can do is familiarize with the early signs of it, and then be on watch for it, in both home gardens and fields, Bisht said.

Symptoms can appear on the plant’s leaves, stems and fruits, said Bisht. Under high humidity or after rains, the infection would show on leaves as brown lesions, sometimes with light-coloured margins and on the underside powdery appearance on the infected areas.

Stem infections are dark brown and can be one cm to five to 10 cm long. These lesions on stems would also show powdery appearance under high humidity.

Any plants suspected of being infected should be sent for diagnosis to MAFRD’s Crop Diagnostic Lab (at 545 University Crescent, Winnipeg, Man.) or turned over to a local MAFRD GO office.

There are precautions growers can take to avoid that spread of the disease too.

Weeds like nightshade and volunteers in last year’s fields, or in potato cull piles can also start the disease.

In potatoes the highly infected tubers will rot in the field itself, but those with low infection get carried into storage when they can’t be graded out.

“Those are the ones that become the source of problem for the next year, if they are seed crop,” says Bisht.

Another source of infection can develop if growers throw culls into a pile expecting them to rot down. Those piles can withstand very cold temperatures through winter and in spring plants may emerge from them, potentially becoming another source for the infection.

One of the critical things all growers can do is share information with neighbours so everyone can take steps to keep it from spreading if it is detected anywhere.

“Since the disease spreads like an epidemic it is important that we all share the information that there is late blight around,” Bisht says.

Other preventive strategies include ensuring tomato seedlings bought from greenhouse growers are healthy to begin with or by purchasing tomato seed only from reputable local suppliers.

There are several late blight-resistant tomato variety options for home growers to choose from, including both hybrids and heirloom varieties, said Bisht.

Hybrids include Defiant, Plum Regal, Mountain Magic, Mountain Merit, Iron Lady and Jasper tomato.

Resistant heirloom tomato cultivars include Lemon Drop, Matt’s Wild Cherry, and Mr. Stripey (Tigerella).

Growers can also keep abreast of where late blight has been detected, and where it may be spreading by checking a regularly updated provincial forecast throughout the growing season. Manitoba Agriculture twice weekly updates the forecast, found on its website at mbpotatoes.ca.

More information about late blight and managing to prevent it is found on MAFRD’s website at: https://www.gov.mb.ca/agriculture/crops/plant-diseases/late-blight-disease-mgmt.html.

The post Get an early start on preventing late blight appeared first on Manitoba Co-operator.

“Health Canada’s Pest Management Regulatory Agency (PMRA) has not banned the import of streptomycin-treated bean seeds,” the federal department said in an emailed statement. “It should be noted, however, that streptomycin sulphate is not currently registered in Canada for use as a coating on bean seeds and importation of streptomycin-treated dry bean seeds from the U.S. for planting in Canada has only been permitted on a limited basis.”

The antibiotic seed coating has not been registered in Canada since 1988 and the PMRA originally told producers that 1998 would be the last year they could import treated seeds from the United States. But after industry lobbying efforts, that deadline was deferred — again and again — while researchers strove to find alternative treatments and develop bean varieties resistant to common blight and halo blight.

Health Canada has stated that growers may import and use streptomycin-treated bean seeds for their 2017 crop, however, any requests to import or use streptomycin-treated bean seeds for the 2018 growing season will be dependent upon applications to register both the streptomycin active ingredient and an end-use product for treating bean seeds.

“We knew this day was coming,” said Bob Conner, a research scientist at the Agriculture and Agri-Food Canada Research Development Centre in Morden. “I think (the PMRA) had postponed the removal of streptomycin sulphate as a seed treatment for a number of years… they gave us enough time that we could start to release resistant varieties, because in the long run, resistance is probably going to be the best option for controlling that problem.”

Resistant varieties elusive

But developing varieties resistant to common blight and halo blight has proved challenging, and Health Canada has indicated that preventing antibiotic resistance is a key motivator in changing regulations around the use of streptomycin sulphate.

“PMRA has recently learned that the research effort has not achieved the intended results,” Eric Morrissette, chief of media relations for the Public Health Agency of Canada, said in an email.

“Furthermore, in order to support the Government of Canada and WHO effort to reduce the potential for development of antimicrobial resistance, it is important that all uses of streptomycin in Canada be properly monitored. As a result, PMRA notified Pulse Canada in July 2016 that applications to register streptomycin for treating bean seeds will be required by June 2017,” said Morrissette. “The PMRA has advised Pulse Canada to work with manufacturers to encourage them to submit applications for registration.”

Needed for humans

Streptomycin is an antibiotic of the first class, which the World Health Organization recently labelled as “essential” for human medicine. It is used to treat tuberculosis and the bubonic plague, the latter of which is estimated to have killed 50 million people during the 14th century and still infects people to this day — cases of the plague caused by the Yersinia Pestis bacteria were documented in Bolivia, Peru, Uganda, China, Tanzania and Russia in 2014. That same year 9.6 million people were diagnosed with tuberculosis and 1.5 million people died from that disease worldwide.

Francois Labelle, executive director of the Manitoba Pulse and Soybean Growers association, said that pulse producers would like to have as many tools in their tool box as possible when it comes to fighting and preventing disease, but he added that resistant varieties would be preferred.

“Developing new varieties takes such a long time that with some of these varieties, you know, it’s hard to say if they’re moving to them or not,” Labelle said, following a field day in Morden this summer. “There’s not been a lot of move to these new varieties yet, but hopefully there will be more and hopefully they’ll be as competitive as the other crops or the ones that are growing today.”

While Pulse Canada declined to provide an interview regarding the issue, it was clear the organization does not view the matter as resolved.

“There are a number of details on this issue that are still being finalized,” said a spokesperson for the organization. “We are not able to comment on it at this time.”

According to Pulse Canada statistics provided by Health Canada, approximately 98 per cent dry bean seeds imported into Alberta are treated with streptomycin prior to importation. In Saskatchewan, 67 per cent of imported dry bean seeds are treated, compared to only five per cent in Ontario.

Numbers were not made available for Manitoba imports, but Labelle said the percentage would be fairly low.

Copper-based products can be used to control blight, but are expensive and usually require more than one application. Even so, the use of imported streptomycin seed was never meant to be a permanent solution, Morrissette said.

“The use of streptomycin imported seed was meant to facilitate transition to other pest control measures,” he added.

The post Antibiotic bean coatings under scrutiny appeared first on Manitoba Co-operator.

Late blight — the same fungal disease responsible for the Irish potato famine in the late 1840s — was detected July 16 in a potato field near Carberry.

Last week there were more than 15 infected fields, Manitoba Agriculture plant pathologist Vikram Bisht said in an interview Aug. 10. Most are in the Carberry area but late blight has also been found near Sydney, Melbourne and Glenboro. The disease was also found in a market garden near Oakville.

“The message to home gardeners is if you… are seeing the (late blight) infection and have not sprayed fungicide the plants will go down and die very quickly,” Bisht said. “The fruit will also get infected and it will appear with brown spots. They don’t store very well.

“If your leaves have infection, harvest as many of the fruits as you can, then destroy the plants. Put them in black garbage bags and keep them in the sun. After two to three days they should get cooked very well and that will destroy the disease. If you throw the plants in the compost pile the plants will not dry quickly enough and will continue to sporulate. Those spores will be a risk to commercial potato producers of Manitoba.”

Lesions

Late blight symptoms are similar on tomatoes and potatoes. Manitoba Agriculture’s website says to look for for small, light to dark green, circular to irregular-shaped, water-soaked spots.

“During cool, moist weather, these lesions expand rapidly into large, dark brown or black lesions, often appearing greasy,” the site says. “The lesions are not limited by leaf veins and as new infections occur and existing infections coalesce, entire leaves can become blighted and die within a few days. The lesions may expand down petioles and stems of the plant.”

Late blight lesion on a tomato leaf.

The late blight strain found in Manitoba is US23, which is very aggressive in tomatoes and potatoes, Bisht said. He suspects the fungal disease spread in high winds during during recent thunderstorms.

Although more than 15 cases of the disease have been found in some cases only a few potato plants were infected, Bisht said. The infected plants have been destroyed.

“The growers are trying to keep on top of it with a five- to seven-day (fungicide) spray schedule,” he said. “Commercial potato growers currently appear to be managing.

“It would be good to see some dry weather because every three or four days we have rain events and that is creating trouble. The commercial potato growers are at risk basically if the home gardeners do not do a good job (controlling late blight).”

Commercial growers can control late blight with fungicides that contain chlorothalonil or mancozeb. Home gardeners can spray copper sulphate.

Air circulation

Garden tomatoes and potatoes are also more susceptible to late blight if plants remain damp, which can occur when plants are thick, preventing air circulation. As a result weedy gardens are more at risk, Bisht said.

Bisht also recommends gardeners buy late blight-resistant tomatoes.

Gardeners should buy new certified seed potatoes next spring and plant healthy-looking tomatoes.

Infected volunteer potatoes could be a disease source and should be destroyed. Volunteer tomatoes come from seed, which doesn’t harbour the disease.

Late blight was found in Manitoba last year, but not until Sept. 11.

So long as the crop is growing it’s susceptible to late blight infection.

Potatoes infected with late blight can rot in storage. Late blight doesn’t rot potatoes, but the damage it causes allows other infections that cause rot to develop.

Treating potatoes with phosphorous acid (Phostrol, Rampart and Confine) as they go into storage can protect them from rot.

Although some fields have suffered due to excess moisture and others have been damaged by hail, most were doing well as of Aug. 12, said Keystone Potato Growers Association Inc. manager Dan Sawatzky.

CORRECTION, Aug. 14, 2016: Late blight symptoms can first appear anywhere on tomato or potato leaves, not just on lower leaves as reported in a previous version of this article.

The post Manitoba potato growers, gardeners need to scout for late blight appeared first on Manitoba Co-operator.

The first case of late blight this season was confirmed Sept. 11 in a commercial potato field in the Carberry area. A second case was found soon after about a mile away.

Last week, a third infection was found in the Carberry area, plus 2 more fields in the Graysville area, and one infection in tomatoes in the Portage la Prairie area, Bisht said in an interview Sept. 18.

“It (late blight) won’t survive our Manitoba weather if it is frozen, but in the compost pile sometimes it survives and they (potato tubers) sprout in the spring,” he said. “With tomatoes, in most cases it will just rot away because there is so much liquid.”

Suspect infections

Bisht wants to hear from gardeners who suspect they have late blight in their tomatoes or potatoes. Photograph suspected infections and email them to vikram.bisht@gov.mb.ca. Samples can also be taken to the MAFRD GO office, 65 3rd Ave. NE, Carman, Man.

Infected tomatoes can spread to a gardener’s potatoes. If infected potatoes are stored and then planted next spring they could be a disease source, Bisht warns.

To avoid that, gardeners should be aware if they have the disease this fall. If so, they should destroy infected potato and tomato plants. Don’t put them in a compost pile where they might not freeze. If infected plants are worked up, then rot and freeze over the winter they will no longer pose a threat.

Gardeners should buy new certified seed potatoes next spring and plant healthy-looking tomatoes.

Infected volunteer potatoes could be a disease source and should be destroyed. Volunteer tomatoes come from seed, which doesn’t harbour the disease.

When late blight strikes a garden earlier in the growing season, Bisht recommends destroying infected plants by placing them in black garage bags and leaving them in the sun. Extreme heat will destroy the disease. Burning infected plants is impractical because of the high moisture content.

Late arrival

The good news is late blight arrived in Manitoba late. Home tomato and potato production is wrapping up, while commercial potato growers are well into harvest. Still, potato farmers need to be vigilant. Some farmers delay harvest to maximize yield. So long as the crop is growing it’s susceptible to late blight infection, Bisht said.

“Scouting is critical now, mainly in wind-sheltered areas and the dips in field where the foliage is greener,” Bisht wrote in a recent report. “Especially for fields which have a few more weeks to harvest, fungicide application to protect the crops is very important. Systemic (translaminar) fungicides could be considered. Dew and rains could take the (disease) spores to tubers close to the surface.”

Potatoes infected with late blight now could rot in storage, Bisht said. Late blight doesn’t rot potatoes, but the damage it causes allows other infections that cause rot to develop.

Treating potatoes with phosphorus acid (Phostrol, Rampart and Confine) as they are placed in storage can protect them from rot, Bisht said.

“Growers need to be scouting and make sure when tubers are going into storage it will help to have a post-harvest application of phosphorus acid fungicide,” he said.

Bisht suspects late blight was delivered by a thunderstorm that hit the Carberry area Sept. 4

“I can say that because the infection is mostly the top of the leaves scattered in a field rather than a big circle or patch within the field,” he said. “If it’s a big patch of disease then you can speculate that it started in that area, but when it’s a few spots here and there then it’s an indication that it came from outside.”

Correction: The number of late blight infections found in the Graysville area — two — was corrected Sept. 23.

The post Late blight hits Manitoba late, but still a concern appeared first on Manitoba Co-operator.

Commercial potato growers should apply fungicides to protect uninfected fields and treat infected ones, but it’s home gardeners Vikram Bisht wants to get a warning to. Potatoes infected with late blight this fall and planted next spring in a garden could be a source of the disease, said Manitoba Agriculture, Foods and Rural Development’s potato and horticultural crops plant pathologist.

“I would emphasize that the tomato home gardeners should look for late blight, especially in those areas (around Carberry),” Bisht said, noting that tomatoes also get the disease. “If they have any suspicions and see funny, large spots and their potatoes might also be getting something, they should report suspicious things to us so we can ensure that it is controlled.

“It’s best to buy new (potato) seed (each spring) that way they don’t risk starting an infection.”

Although Manitoba’s processing potatoes are close to harvest, many plants are still vulnerable, he said. To maximize yield processing potatoes tend not to get desiccated.

“Growers need to spray (a fungicide) if they are planning to hold the crop for a couple more weeks,” Bisht said.

The first case of late blight this season was confirmed in a sample received Sept. 11. The following day infection was found mostly on the top foliage and fine branches of some potato plants, Bisht said in the Sept. 14 Potato Disease Report.

“The sample was confirmed positive for sporangial production,” he wrote.

A second case was found in another field about a mile away.

“Scouting is critical now, mainly in wind sheltered areas and the dips in field where the foliage is greener compared to the senescing crop around,” Bisht wrote. “Especially for fields which have a few more weeks to harvest, fungicide application to protect the crops is very important. Systemic (translaminar) fungicides could be considered. Dew and rains could take the (disease) spores to tubers close to the surface. There is a forecast of precipitation in the mid-week.”

Potatoes infected with late blight now could rot in storage, Bisht said. Late blight doesn’t rot potatoes, but the damage it causes allows other infections to develop resulting in rot.

Treating potatoes with phosphorus acid (Phostrol, Rampart and Confine) as they are placed in storage can protect them from rot, Bisht said.

“The better the coverage, the better security you have for good storage,” he added.

Late blight doesn’t normally overwinter in Manitoba. Bisht suspects the latest infection was delivered by a thunderstorm that hit the area Sept. 4.

“I can say that because the infection is mostly the top of the leaves scattered in a field rather than a big circle or patch within the field,” he said. “If it’s a big patch of disease then you can speculate that it started in that area, but when it’s a few spots here and there then it’s an indication that it came from outside.

“People in that corridor east and west of Carberry probably need to scout their fields to ensure they don’t have late blight,” Bisht said.

The post Manitoba’s first late blight infection found in potato field near Carberry appeared first on Manitoba Co-operator.

Flea beetles in canola and cutworms continue to be the insects of greatest concern. Insecticide applications and some reseeding have occurred because of feeding by these insects.

Monitor emerging crops for seedling disease. So far populations of disease vectors have been low. Aphid vectors of barley yellow dwarf have not been seen or reported, and only small populations of aster leafhopper have been reported so far; these should not be of concern in field crops.

Canola

Flea beetles continue to be a concern in many areas of Manitoba, with foliar insecticide applications being needed in many regions. Canola plants will become less vulnerable once 3 or 4 true leaves have emerged.

The flea beetle that are present in canola fields currently are the same flea beetles that were present late last summer and overwintered. These are starting to die off and by late June populations of adult flea beetles get quite low.

No new adult flea beetles are being added to the population in the spring and early summer, these are only those surviving through the winter. New flea beetles produced this year will start showing up in late summer.

Cereal Crops

Wheat Streak Mosaic: A winter wheat sample from the Eastman region has tested positive for Wheat Streak Mosaic. This disease is caused by a virus and vectored by the wheat curl mite. The disease and mite overwinter on winter wheat and the mites are easily moved from field to field with the wind. Field edges, especially in spring wheat fields near winter wheat fields, should be scouted for the presence of this disease. Common symptoms include chlorotic stripes on the leaves running parallel to the veins. Plants may also appear stunted and the leaf edges may curl upward and inward.

Fusarium Head Blight: Winter wheat across the province is nearing the flowering stage where a fungicide application for Fusarium Head Blight may be warranted. The provincial Fusarium Head Blight risk maps will be published on the MAFRD website starting mid-June. These maps provide broad information on current risk of FHB infection; individual fields should be scouted as local conditions will vary.

Insects and Pathogens in Multiple Crops

Cutworms: Cutworms continue to be of concern, with insecticide applications for cutworms being reported over the past week in sunflowers, soybeans, and dry beans.

The stage of growth the larvae are in will depend on the species and temperatures the larvae have been exposed to, with quicker development under warmer temperatures. In some fields cutworms may remain in the larval stages for another week or two before starting to turn to pupae, after which their damaging stage will be complete. The stage of cutworms can vary between fields. Larvae of redbacked cutworms, which seems to be one of our common species this year, get to be about 38 cm long (about 1.5 in.) when fully grown. After this they will turn to pupae. So in addition to the amount of cutworms and amount of feeding occurring to the crop, this time of year it is good to consider the size of the cutworms in decision making. If most are quite large their feeding will be ending soon. Also consider whether populations in a field are patchy, as is often the case.

Threshold for cutworms in soybeans and dry beans: One of the common questions this week was is there an economic threshold for cutworms in soybeans. The short answer is no. No studies have been done to produce a proper economic threshold for cutworms in soybeans. There are however, nominal thresholds that can be used as guidelines. Nominal thresholds are based on experience and the best available information, rather than research quantifying the impact of the insect on the crop.

Nominal threshold that may be used for cutworms in soybeans and dry beans are 1 or more larvae per three feet of row and larvae are small (less than 2 cm), or 20 per cent of plants cut.

Soybeans are a crop that is quite good at compensating for defoliation. So it is good to note how much clipping of plants is occurring. Different species of cutworms may result in different levels of stem clipping.

Insect Monitoring Programs

Diamondback Moth: The following are the highest cumulative counts for the traps for adult diamondback moth in Manitoba from April 26 to June 9, 2015.

The post Manitoba crop insect and disease update – June 9, 2015 appeared first on Manitoba Co-operator.

Five cases of the fungal disease responsible for the Irish Potato Famine in the 1840s, have been detected in potatoes, including in a “sentinel” plot at the Canada-Manitoba Crop Diversification Centre near Winkler last week, said Vikram Bisht, a plant pathologist with Manitoba Agriculture Food and Rural Initiatives (MAFRI).

The four other infected potato fields were near Holland, Carberry, Winkler and Carman.

“Though the number of fields affected and the severity of late blight is low, the inoculum is present in a wider swath of the province,” Bisht wrote last week in theMB Potato Newsnewsletter. “It is now critical for potato growers and home gardeners to monitor their crops for late blight. Irrigated potato fields and crops protected from wind or in river flats often have dew on the plants for long duration and could be prone to late blight infection.”

Tomatoes, potatoes, the petunia, tomatillo and weed nightshade plants all are susceptible to late blight.

There are many strains of late blight, some of which are more aggressive on tomatoes than potatoes and vice versa, Bisht said in an interview.

In the early stages of infection, the disease appears as water-soaked grey-green lesions on leaves and/or stems, Bisht wrote inMB Potato News.

With high humidity, the fungus will produce spores on the underside of leaves appearing as a white mildew-like growth on the leaves and stems. As the tissue dies, it turns grey to brown and dries up within a few days. Late blight spores are microscopic and are spread both by splashing rain and wind, which can carry them many miles.

However, not all spots on tomatoes or potatoes are necessarily late blight. If there are concentric rings of light-and dark-brown circles, often not crossing the veins and spots do not have white sporulation even under high humidity it could be early blight, another fungal disease.

“Early blight usually appears when the plants are nearing end of season or on plants with nutrient stress, but it is often not as devastating as late blight,” Bisht wrote.

Samples of diseased plants can be sent to MAFRI’s Crop Diagnostic Lab, 545 University Crescent, Winnipeg, MB or your local MAFRI GO office for a diagnosis. Non-commercial growers are subject to a $10 fee.

Samples should be packaged in containers that can breathe and be kept moist.

Late blight decimated tomatoes in gardens across the province in 2010, aided by extremely wet conditions.

Bisht has the following tips to manage late blight:

Buy certified seed potatoes to reduce the risk of introducing late blight.

Select tomato seedlings that appear healthy.

Keep a close watch on your tomato and potato plants during the growing season.

Preventive fungicide sprays may be applied if late blight is present in your neighbourhood.

Remove plants that show symptoms of the disease. Infected plants should be dug up, destroyed and disposed of properly to prevent the disease from spreading.

As a preventive measure, four compounds are registered for domestic use in home gardens as protectant fungicides. All are copper based.

King ECO-Way PTV Potato, Tomato &Vegetable Fungicide Spray (Wettable Powder).

King PTV Potato, Tomato &Vegetable Dust for Bugs and Blights (Insecticide/Fungicide Dust).

Green Earth BORDO Copper Spray (Wettable Powder).

Wilson Garden Doctor Insecticide/Fungicide (Dust formulation).

Contact your local home and garden centres for these products.

Don’t compost diseased plants. Carefully remove them and put them in plastic bags. Double bagging helps keep the spores from spreading. Set the plastic bags in the sun to heat the infected material enough to kill the plants.

Commercial potato growers who discover a localized late blight infection should use a restricted burn-off with Reglone plus a fungicide. If a hot spot can’t be identified immediately apply a fungicide with curative action. A five-day spray schedule is recommended.

In Prince Edward Island 21 cases of late blight have been confirmed, including on volunteer potato plants in a soybean field, Bisht wrote. For that reason volunteers should be controlled. allan@fbcpublishing.com

———

“Itisnowcriticalforpotatogrowersandhome gardenerstomonitortheircropsforlateblight.”

– VIKRAM BISHT

The post Late Blight Found In Tomatoes appeared first on Manitoba Co-operator.