Williston Research Extension Center

Accessibility


WREC Plant Pathology Updates

| Share

Lentil Disease Diagnostic Series (PP1913)

A new flip book to aid in disease identification in lentils is now available from NDSU as a hard copy and digital format.

The new lentil disease diagnostic series features high quality images of diseases along with descriptions to help identify symptoms.

The series can be viewed online here:

https://www.ag.ndsu.edu/publications/crops/lentil-disease-diagnostic-series

If you would like to obtain a hard copy a limited quantity are available. To order contact me at audrey.kalil@ndsu.edu

The book was produced as a collaborative effort of the Pulse Crop Working Group funded by the North Central IPM Center.

North Central IPM Center logo

| Share

2018 Pulse Crop Survey – Insect Pest Report

Author: Dr. Janet Knodel, Extension Entomologist

NDSU pulse crop scouts (WREC: Shawn Postovit, NCREC: Graysyn Kitts) surveyed field pea, lentil and chickpea fields in northwest and north central North Dakota for insect pests from late May until early August. A total of 218 chickpea fields, 51 lentil fields, and 29 field pea fields were scouted. A summary of selected insect pests are discussed below.

Cutworms were observed in all three pulse crops surveyed but only present early in the crop growing season from late May to mid-June. The overall percentage of fields infested with cutworms was low – 8% of lentils fields, 3% of field pea fields and <1% of chickpea fields. The northwest area of ND had the highest densities of cutworms.

 

Pea aphids - Scouts collected aphids using 20 180-degree sweeps in each field at 5 spots. Pea aphids were most common later in the field season, usually late July into early August, and were only economic in 10% of the lentils scouted and <1% of the chickpea field scouted. Pea aphids were absent from the 29 field pea fields scouted. The hot spot for pea aphids was in Williams and Burke Counties. Otherwise, pea aphids were not a major problem in most of the pulse crop areas in 2018.

Pea leaf weevil (Sitona lineatus) is a new insect pest of field pea that was first discovered in the fall of 2016 near Beech, ND. In 2017, additional survey work found pea leaf weevils in field pea or faba beans fields the following areas: southwest (Dunn, Golden Valley and Stark counties), north-central (Mountrail and Ward counties) and northwest (Divide County). In 2018, pulse crop scouts and the IPM scout (Marc Michaelson from Dickinson REC) looked for feeding injury (leaf notching) of pea leaf weevil by examining 100 plants per field. Leaf notching was found over a wider range than previous years. Five new county records were documented in 2018 including Billings, Bowman, Hettinger and Slope Counties in southwest and Mercer County in west central. This survey focuses on number of leaf notches caused by adult feeding, and not the yield depriving larval feeding on the nitrogen-fixing root nodules. When the number of leaf notches are greater than 9 notches per plant (yellow square or red triangle on map), economic damage (yield loss) can be significant if conditions are favorable for pea leaf weevil in the spring of 2019 (warm springs >68F). Only Billings and Slope Counties had leaf notching greater than 9 notches per plant. Pulse producers should use this information along with field history of pea leaf weevil abundance to make decisions for the 2019 crop year. Research has demonstrated that insecticide seed treatments are more effective in reducing losses due to pea leaf weevil than foliar insecticides. Please see the new extension publication Integrated Pest Management of Pea Leaf Weevil in North Dakota E1879, April 2018, for more information.

knodel.9

knodel.10

Thanks to the Northern Pulse Growers Association for funding this survey.

 

| Share

2018 Pulse Crop Disease Scouting Summary

NDSU pulse crop scouts (WREC: Shawn Postovit, NCREC: Graysyn Kitts) surveyed field pea, lentil and chickpea fields in northwest and north central North Dakota for diseases from late May until early August. Regular rainfall during the growing season led to environmental conditions suitable for disease development in all three crops.

NDSU pulse crop scouts (WREC: Shawn Postovit, NCREC: Graysyn Kitts) surveyed field pea, lentil and chickpea fields in northwest and north central North Dakota for diseases from late May until early August. Regular rainfall during the growing season led to environmental conditions suitable for disease development in all three crops.

Anthracnose and white mold were the primary foliar diseases observed in lentils this growing season. Anthracnose onset was in mid-July when the fields scouted were at the early pod growth stage. Incidence of diseased plants reached up to 18% in some fields (Figure 1). White mold was present in 60% of fields scouted from mid-July to early August with incidence ranging from 1-26% (Figure 1).

kalil.1

Bacterial blight symptoms were observed in field pea beginning in early June when the crop was at late vegetative to early reproductive growth stages. Incidence reached 40-50% in some fields (Figure 2) with 2-18% of the crop canopy exhibiting symptoms. White mold was not observed in pea fields.

kalil.2

Onset of Ascochyta blight in chickpea was in mid-June, when the crop was at mid to late vegetative growth stages. Fields varied greatly in incidence and severity of Ascochyta symptoms (Figure 3). In some fields, the percent of plants showing symptoms stayed below 4% throughout the survey, while in others incidence reached 100% by mid-July. The differences observed among fields were most likely due to the amount of the fungal pathogen present in fields (inoculum), rainfall and fungicide application timing.

kalil.3

Thank You to all the producers who participated in the pulse crop scouting effort!

 

The Northern Pulse Growers Association funded this work.

 

| Share

Pulse Crop Update (07/12/18)

Pea fields in the northwest part of the state have reached early to late reproductive growth stages (Figure 1).   Lentils and chickpeas are a little behind the pea crop, but most fields in the northwest region have reached bloom. 

kalil.1

Disease levels in lentil fields have remained low.  Out of the eleven lentil fields scouted by the NDSU WREC pulse scout (Shawn Postovit) from June 18th – 29th, only one field was positive for foliar disease (Ascochyta Blight – Figure 2). With the crop having reached canopy closure in many fields and the weather remaining wet in this region, we will continue to scout for foliar diseases, as high humidity within the crop canopy will favor disease.

kalil.2

Bacterial blight has been identified in pea fields in Williams, Burke and Mountrail counties (Figure 3).  Incidence ranges from 8 – 48% of plants exhibiting symptoms. Severity is generally low, with under 15% of the crop canopy showing symptoms.  More information about bacterial blight can be found on a previous article in the crop and pest report from 6/2/16 titled Field Pea Diseases Review: Bacterial Blight and Brown Spot.  

kalil.3

Scouting of chickpea fields in the northwest and north central region of the state for Ascochyta blight continues. In some fields incidence has reached up to 80% (Figure 4). The percent of the crop canopy exhibiting symptoms was on average 7% in the sixteen fields that were positive for disease. Many of these fields have been treated with fungicides in recent weeks.

kalil.4

More information about management of chickpea Ascochyta blight can be found on a previous article in the crop and pest report from 6/28/18 titled Management Recommendations for Ascochyta Blight on Chickpea.

 

| Share

Pulse Crop Disease Update (06/21/18)

Ascochyta blight has been found by an NDSU pulse crop scout (Shawn Postovit) in chickpea fields in Williams and Burke Counties at up to 50% incidence.

Ascochyta blight has been found by an NDSU pulse crop scout (Shawn Postovit) in chickpea fields in Williams and Burke Counties at up to 50% incidence. Ascochyta first appears as scattered disease lesions on plants (Fig 1) but this disease can progress very quickly and thus foliar fungicides must be applied in a timely manner. Applications of systemic fungicides are advised as soon as trace levels of disease is detected. If weather remains cool and wet, applications of fungicides should continue every 10 to 14 days during bloom and early pod fill. Note that Strobilurin (FRAC 11) fungicides are not effective on Ascochyta blight on chickpeas as the pathogen, Ascochyta rabiei, has developed resistance. Further management recommendations can be found in the publication Management of Ascochyta Blight of Chickpea found on the Pulses: Tools for Growers webpage. Refer to the 2018 North Dakota Field Crop Plant Disease Management Guide for products currently registered on chickpea in ND.

 kalil

| Share

Increasing Levels of Root Rot Observed in Lentils in NW ND (07/14/16)

Analysis of root rot samples collected during field scouting (Adam Carlson, NDSU & Kim Zitnick, NDSU) has revealed increasing incidence and severity of root rot in lentils across northwest ND (Fig 1). Root rotting and wilt-causing Fusarium pathogens have been most commonly isolated. The frequency of Pythium has increased recently, whereas Aphanomyces euteiches has only been detected from one field. Rhizoctonia solani thus far has not been observed. Frequent rain and resulting high soil moisture is most likely responsible for the observed increase, in combination with the seed treatment fungicides no longer being effective at this point in the season.

Determination of the casual organism is important in the case of root rot as not all seed treatment fungicides are effective against all pathogens. There are currently no seed treatments available for control of Aphanomyces in peas and lentils. Rotating out of peas and lentils for 4-6 years can help reduce the buildup of these pathogens, although note that some root rotting pathogens can infect other broadleaf crops.

kalil.1

For more information about root rot diseases of pulses see the new Pea Disease Diagnostic Series (NDSU), as well a publication from Canadian pulse growing associations, “Root Rot in Pea and Lentil in Western Canada”.

 

Audrey Kalil

Plant Pathologist

NDSU Williston Research Extension Center

 Julie Pasche

Assistant Professor, NDSU Plant Pathology

 Kim Zitnick-Anderson

Post-Doctoral Researcher, NDSU Plant Pathology

 

| Share

Pea and Lentil Disease Update (07/28/16)

Pea and Lentil Disease Update

Scouting of peas and lentils in Burke, Williams, Divide, Mountrail and McKenzie Counties for foliar disease continues as earlier planted crops start to come off the field (Adam Carlson, Crop Scout NDSU). In pea, ascochyta blight is commonplace in fields, with the highest incidence found in Mountrail County, but severity levels remain low as they have for most of the season (Fig 1). We are beginning to see white mold in some fields in Williams and Divide Counties, and powdery mildew has been observed in McKenzie County (Fig 1). Bacterial blight has been identified in all pea fields scouted (Fig 1). kalil.1                                                                                                                                                                                    In lentils, ascochyta blight and anthracnose were almost universally present in Divide, Williams and McKenzie Counties but severity levels were low (Fig 2).

kalil.2

 

Audrey Kalil

Plant Pathologist

NDSU Williston Research Extension Center

| Share

Incidence of Ascochyta Blight in Peas and Lentils in Northwest ND (06/23/16)

Incidence of Ascochyta Blight in Peas and Lentils in Northwest ND

Scouting of pea and lentil fields in NW ND has revealed low incidence of Ascochyta Blight in lentils (Fig 1), and low to moderate incidence in field pea (Fig 2) so far this season, however, cool and wet conditions in the forecast may lead to increased incidence of this disease. 

ppth.8

If timed appropriately, fungicides can be effective for management of Ascochyta Blight and Canadian researchers recommend using the following guidelines for making a treatment decision (Fig 3):

  • Scout the same 4 locations in your field every 3-5 days from V10 through bloom
  • Assign points to stand, leaf wetness, 5 day weather forecast and disease severity. 
  • If the total number of points exceed 65 AND disease symptoms are present, a fungicide treatment may be warranted.

ppth.9

Also available at this website: http://reducedtillage.ca/docs/Ascochyta_Scoring_System_2006.pdf

Note: These guidelines have not been specifically tested for conditions in North Dakota and should serve only as a reference. 

When scouting, remember that it is critical to distinguish this disease from Bacterial Blight, which will not respond to fungicide treatment. For information about distinguishing Ascochyta blight from bacterial blight of peas see the bulletin Mycosphaerella (Ascochyta) blight and bacterial blight of peas.  For more information about Ascochyta Blight refer to the June 2nd article published this year in the Crop & Pest Report: Field Pea Diseases Review: Ascochyta /Mycosphaerella Blight.

Audrey Kalil

Plant Pathologist, NDSU Williston Research Extension Center

| Share

Pea Enation Mosaic Virus Detected in Divide County (06/16/16)

Pea Enation Mosaic Virus Detected in Divide County

Be on the lookout for Pea ppth.kalil.1Enation Mosaic virus (PEMV). A pea plant exhibiting interveinal chlorosis was found by a crop scout in a field in southern Divide County (Fig 1). Genetic based lab testing by the MSU Regional Pulse Crop Diagnostic Laboratory found that the plant was infected with PEMV. PEMV is a viral disease that can infect many legumes including pea, chickpea, faba bean and lentil and is transmitted by pea aphid and green peach aphid, in addition to several other aphid species. Symptoms can vary based on host and environment, but infected plants will typically develop yellow or translucent flecks on the leaf (Fig 2A), vein clearing and later on “enations” or leaf blisters may appear (Fig 2B). Leaves might also be twisted or edges may have a downward roll. These early symptoms can easily be confused with herbicide damage, nutrient deficiency or other viruses, so laboratory diagnoses is important. PEMV may also cause stunting and a reduction in internode length. Pods may be twisted, deformed or develop a “warty” appearance (Fig 2C). If the plant is infected prior to bloom, pods may not fill normally and yield may be impacted.

ppth.kalil.2Few management options exist for PEMV. Reducing aphid populations with an insecticide application may reduce the secondary spread of the virus. However, it is unclear if that application would be cost-effective. In planning for next year resistance could be an option. Hampton, a PEMV resistant green field pea variety was released, and although it was developed for conditions in the Pacific Northwest, it may be a good option for growers who have problems with this disease.

Audrey Kalil

Plant Pathologist, NDSU Williston Research Extension Center

| Share

Pea Seed-borne Mosaic Virus Detected in One Seed Lot from Mountrail County (05/19/16)

Pea Seed-borne Mosaic Virus (PSbMV) is a viral disease that can cause substantial yield and quality losses in lentils and peas and can also infect chickpeas, faba beans and vetches.

Pea Seed-borne Mosaic Virus (PSbMV) is appth.kalil.pea viral disease that can cause substantial yield and quality losses in lentils and peas and can also infect chickpeas, faba beans and vetches.  Plant symptoms include stunting, pod and leaf deformation, and delayed maturation (Fig 1. top). Seeds may be smaller, and discolored with split seed coats (Fig. 1 bottom). As the name implies the virus can infect the seed and when this seed is planted the virus can spread into the plant.  The transmission rate from seed to plant is on average 30% in peas and 44% in lentils. Aphid feeding transmits the virus from infected plants to new hosts during the growing season. Therefore, planting infected seed and high aphid populations put you at the greatest risk for PSbMV.

As part of a NW ND pulse scouting project funded by the Northern Pulse Growers Association, Taheni Jbir (Crop Scout, NDSU WREC) and Dr. Audrey Kalil (Plant Pathologist, NDSU WREC) collected pea and lentil samples from growers in Williams, Divide, Mountrail, McKenzie and Burke Counties.

A total of 10 lentil and 18 pea samplesppth.kalil.pea.2 were collected and analyzed by the NDSU Plant Diagnostic Lab for PSbMV (Fig 2). Low levels of PSbMV were detected in a single pea seed lot from Mountrail County, all other lots were negative for the virus. These results, from a limited number of seed lots, suggest that overall levels of PSbMV in planted seed may be low in NW ND; however, it remains important to scout for aphids weekly up through pod development as this virus can be transmitted very rapidly under high aphid pressure.

Remember that PSbMV infected seed should not be saved and as infected seed may be symptomless, it is recommended to get seed tested for this disease. To submit your seed for testing contact the NDSU Plant Diagnostic Lab https://www.ag.ndsu.edu/pdl

For more information on PSbMV and management options see the NDSU publication Pea Seed-borne Mosaic Virus (PSbMV) in Field Peas and Lentils (PP1704).

| Share

2015 Wheat Midge Survey Results

The results of the 2015 survey for Wheat Midge Larvae have been reported. Samples were collected in harvested wheat fields in the fall of 2015 and results predict wheat midge populations for the 2016 growing season. According to Dr. Janet Knodel, NDSU Extension Entomologist, "No soil samples were found with economic population densities of wheat midge (greater than 500 midge larvae per square meter) this past year."  The majority of the samples, in fact, did not contain any wheat midge cocoons. This is good news for wheat growers and should reduce insecticide costs in the 2016 season. 

 

2015 Wheat Midge Survey Results

For more information about the results of this survey see the article below:

https://www.ag.ndsu.edu/extensionentomology/field-crops-insect-pests/Documents/wheat-midge-information/2015/2015_2016%20wheat%20midge%20survey%20Knodel_News%20Release_FINAL.pdf

Creative Commons License
Feel free to use and share this content, but please do so under the conditions of our Creative Commons license and our Rules for Use. Thanks.