June 23, 2017

Lindsey du Toit – WA State Commentary – Onion ipmPIPE

onion_flowers

2013 WA – Onion ipmPIPE Commentary 7-24-2013

COLUMBIA BASIN OF NORTHCENTRAL OREGON AND CENTRAL WASHINGTON Commentary 7/24/2013

 

Onion Crop Growth Stage and Status Last Modified: 07/24/13

Onion crops are maturing rapidly with the very warm conditions in the Columbia Basin in July. Bulb crops in the north Columbia Basin are at the 5-6 growth stages (12 pairs of true leaves and bulb initiation), and in the south Basin most crops are at the 6-7 growth stages (bulb diameter of 1.0-1.75 inches and 1.75-3.0 inches = 2.0-4.0 cm and 4.0-7.5 cm diameter, respectively).

 

Seed crops of Allium fistulosum (bunching onion) have been harvested. A. cepa and CFC (‘cepa fistulosum cross’) seed crops are in late-bloom.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 07/24/13

July has been very warm in the Columbia Basin, with the result that thrips numbers have increased significantly.

 

Temperature Outlook* [next 2 – 4 weeks]:       average

Precipitation Outlook* [next 2 – 4 weeks]:        average to 30% below average

*Courtesy of Planalytics, Inc.

 

Insect Scouting, Outlook and Management Last Modified: 07/24/13

Thrips

Thrips populations have increased very rapidly in onion crops with the onset of very warm conditions through most of July. 100% of plants were infested in Sentinel Plots in the north and south Columbia Basin, with 3 to 35 thrips/plant detected in the north Basin Sentinel Plots, and 5-69 thrips/plant in the south Basin Sentinel Plots.

 

Maggots

No maggot problems reported at this time.

Other

None reported.

 

Disease Scouting, Outlook and Management Last Modified: 07/24/13

Iris yellow spot virus

Iris yellow spot virus has been detected in several onion bulb fields in the north and south Columbia Basin. In the north Basin, the infected crops are in relatively close proximity to onion seed crops infected with IYSV. Samples were submitted to the NOVL on 7/16/2013. Growers leasing ground have been advised to consider the location of biennial onion seed crops in the region to try and avoid a green bridge effect for movement of thrips and IYSV from seed crops to bulb crops.

 

Soilborne Diseases (Damping-off, pink root, Fusarium basal rot, etc.)

Pink root observed on 2-6% of the plants in Sentinel Plots in the south Columbia Basin.

 

Fungal Foliar Diseases (purple blotch, downy mildew, Botrytis)

No surveys or reports at this time.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots)

A few growers reported bacterial-like symptoms in center-pivot irrigated bulb crops in the south Columbia Basin, but there has not yet been verification of the cause of the symptoms on samples tested in one lab. The NOBL in Pullman requested samples for further evaluation.

 

State Contact for Project
Lindsey du Toit
Professor of Plant Pathology

Washington State University
Email: dutoit@wsu.edu

 

Collaborators: Tim Waters, Carrie Wohleb, Jordan Eggers, Hanu Pappu, Brenda Schroeder,

Bill Dean

 

Lindsey du Toit – WA State Commentary – Onion ipmPIPE

onion_flowers

2013 WA – Onion ipmPIPE Commentary 7-10-2013

COLUMBIA BASIN OF NORTHCENTRAL OREGON AND CENTRAL WASHINGTON Commentary 7/10/2013

 

Onion Crop Growth Stage and Status Last Modified: 07/10/13

Onion crop growth continues to progress normally across the Columbia Basin. Crops in the north Basin are at the 7-9 leaf stage of growth (growth stage 4 to 5), and in the south Basin most crops are at the 8-12 leaf (growth stage 5) stage or the 2.5-4.0 cm diameter bulb stage (growth stage 6).

 

Seed crops of Allium fistulosum (bunching onion) are mostly done pollinating. A. cepa and CFC (‘cepa fistulosum cross’) seed crops are in mid- to late- full bloom, respectively.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 07/10/13

A sudden, very hot period from late June through the first week of July, following an extended rainy, cool period may have created stress for some bulb and seed crops. There is concern about the A. cepa and CFC seed crops, in particular, as the high temperatures (up to 108oF) can have a very negative effect on pollination by reducing nectar flow and honey bee activity. Most A. fistulosum seed crops may have escaped the heat in terms of pollination. The heat wave is also likely to affect thrips numbers.

 

Temperature Outlook* [next 2 – 4 weeks]:    30-40% above average

Precipitation Outlook* [next 2 – 4 weeks]:    30-40% below average

*Courtesy of Planalytics, Inc.

 

Insect Scouting, Outlook and Management Last Modified: 07/10/13

Thrips

Thrips populations have increased rapidly in onion bulb crops with the onset of very warm conditions. 100% of plants were infested in Sentinel Plots in the south Columbia Basin, at 3 to 50 thrips/plant; and 100% of plants infested with thrips in Sentinel Plots in the north Columbia Basin, at 4 to 26 thrips/plant.

 

Maggots

No maggot problems reported at this time.

Other

Leafminer observed on 6% of the plants in one Sentinel Plot in the south Columbia Basin.

 

Disease Scouting, Outlook and Management Last Modified: 07/10/13

Iris yellow spot virus

No reports at this time from the NOVL or growers.

 

Soilborne Diseases (Damping-off, pink root, Fusarium basal rot, etc.)

Pink root observed on 2 to 4% of the plants in Sentinel Plots in the south Columbia Basin. Rhizoctonia stunted patches becoming less apparent as the canopy closes on most crops.

 

Fungal Foliar Diseases (purple blotch, downy mildew, Botrytis)

No surveys or reports at this time.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots)

No further samples from the NOBL or comments from growers at this time.

 

State Contact for Project
Lindsey du Toit
Professor of Plant Pathology

Washington State University
Email: dutoit@wsu.edu

 

Collaborators: Tim Waters, Carrie Wohleb, Jordan Eggers, Hanu Pappu, Brenda Schroeder,

Bill Dean

 

Lindsey du Toit – WA State Commentary – Onion ipmPIPE

onion_flowers

2013 WA – Onion ipmPIPE Commentary 6-26-2103

COLUMBIA BASIN OF NORTHCENTRAL OREGON AND CENTRAL WASHINGTON Commentary 6/26/2013

 

Onion Crop Growth Stage and Status Last Modified: 06/26/13

Onion crop growth continues to progress as ‘normal’ for most crops across the Columbia Basin. Crops in the north Basin are at the 5-7 true-leaf stage of growth, and in the south Basin most crops are at the 6-9 true-leaf growth stage.

 

Onion seed crops of Allium fistulosum (bunching onion) are nearing the end of pollination. A. cepa seed crops are in full bloom with bee hives active in all the crops.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 06/26/13

Warm, sunny weather typical of the Columbia Basin of central Washington and northcentral Oregon was replaced with unusually wet conditions for an extended period of more than a week, despite the earlier forecast of normal precipitation or 40% below normal. The forecast for very warm/hot conditions over the next week or two may result in some stress to the crops after this cool, moist period. Precipitation over the past week may result in some foliar diseases in the few weeks that are seldom of concern in the Columbia Basin.

 

Temperature Outlook* [next 2 – 4 weeks]:    60-70% above average

Precipitation Outlook* [next 2 – 4 weeks]:    30% below average

*Courtesy of Planalytics, Inc.

 

Insect Scouting, Outlook and Management Last Modified: 06/26/13

Thrips

Thrips populations have increased rapidly in onion bulb crops, with 100% of the plants infested in Sentinel Plots in the south Columbia Basin, at a range of 2 to 20 thrips/plants, and 88 to 92% of plants infested with thrips in Sentinel Plots in the north Columbia Basin, at 6 to 12 thrips/plant.

 

Maggots

No further maggot problems reported.

Other

Leafminer observed on 5% of the plants in one of the Sentinel Plots in the south Columbia Basin.

 

Disease Scouting, Outlook and Management Last Modified: 06/26/13

Iris yellow spot virus

No reports at this time.

 

Soilborne Diseases (Damping-off, pink root, Fusarium basal rot, etc.)

Pink root observed on 10 to 20% of the plants examined in one of the Sentinel Plots in the south Columbia Basin. Rhizoctonia stunted patches are very evident now as the canopy begins to close in most crops.

 

Fungal Foliar Diseases (purple blotch, downy mildew, Botrytis)

No surveys or reports at this time.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots)

No further samples or comments received from growers at this time.

 

State Contact for Project
Lindsey du Toit
Professor of Plant Pathology

Washington State University
Email: dutoit@wsu.edu

 

Collaborators: Jordan Eggers, Hanu Pappu, Brenda Schroeder, Tim Waters, Carrie Wohleb, Bill Dean

 

Lindsey du Toit – WA State Commentary – Onion ipmPIPE

onion_flowers

2013 WA – Onion ipmPIPE Commentary 6-05-2103

COLUMBIA BASIN OF NORTHCENTRAL OREGON AND CENTRAL WASHINGTON Commentary 6/05/2013

 

Onion Crop Growth Stage and Status Last Modified: 06/05/13

Onion crop growth appears to be normal for most crops across the Columbia Basin. Crops in the north Basin are at the 3-4 true-leaf stage of growth, and in the south Basin most crops are at the 4-6 true-leaf growth stage.

 

There continue to be some herbicide-injury problems reported across the Basin.

 

Onion seed crops of Allium fistulosum (bunching onion) are flowering, and growers are beginning to place beehives in the crops. A. cepa seed crops are at “candle tip” growth stage, and it will be a few weeks before pollination begins. Seed crops appear to be ahead by a week or two compared to 2012. There have been no reports of significant problems in onion seed crops.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 06/05/13

Unusual symptoms of chlorotic yellow bands reported by numerous growers across the Columbia Basin, from Oregon to Quincy. The symptoms appear to be related to environmental stress associated with sudden hot periods (temperatures >90oF) after extended periods of cool, overcast weather. The long periods of cool, overcast weather may have limited development of the waxy layer on leaves of the young plants, with the result that the leaves were prone to heat stress when conditions suddenly got very warm. The problem may be exacerbated by phytotoxicity associated with herbicides applied around the time of major temperature swings. This is being investigated further.

 

Temperature Outlook* [next 2 – 4 weeks]:    30% above average

Precipitation Outlook* [next 2 – 4 weeks]:    0 – 40% below average

*Courtesy of Planalytics, Inc.

 

Insect Scouting, Outlook and Management Last Modified: 06/05/13

Thrips

Thrips populations are starting to develop in onion bulb crops, but are still relatively low. Thrips incidence in the north Columbia Basin ranged from 15 – 25% of plants infested with 0.4 – 3.4 thrips/plant; and in the south Columbia Basin from 0 – 3 thrips/plant.

 

Maggots

The severe seed corn maggot problems reported earlier in the season are tailing off as crops are mostly beyond the susceptible stage of growth.

Other

No other insect reports at this time.

 

Disease Scouting, Outlook and Management Last Modified: 06/05/13

Iris yellow spot virus

No reports at this time.

 

Soilborne Diseases (Damping-off, pink root, Fusarium basal rot, etc.)

Rhizoctonia stunted patches continue to show on coarse, sandy soils in the Columbia Basin following cereal cover crops. The patches of stunted plants become more evident after the crops reach the 4-5 true-leaf stage of growth.

 

Fungal Diseases (purple blotch, downy mildew, Botrytis)

No surveys or reports at this time.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots)

No samples or comments received from growers at this time.

 

State Contact for Project
Lindsey du Toit
Associate Professor of Plant Pathology

Washington State University
Email: dutoit@wsu.edu

 

Collaborators: Jordan Eggers, Hanu Pappu, Brenda Schroeder, Tim Waters, Carrie Wohleb, Bill Dean

 

Lindsey du Toit – WA State Commentary – Onion ipmPIPE

onion_flowers

2013 WA – Onion ipmPIPE Commentary 4-24-2103

COLUMBIA BASIN OF NORTHCENTRAL OREGON AND CENTRAL WASHINGTON Commentary

 

Onion Crop Growth Stage and Status Last Modified: 04/24/13

Planting of onion bulb crops is in full swing, with a majority of storage onion crops planted in the south Columbia Basin, and planting progressing in the north Basin. Emergence has been slow with the cool conditions in March/April.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 04/24/13

The Columbia Basin experienced a relatively mild winter, which means many of the overwintered cereal cover crops commonly planted preceding onion bulb crops, were much taller than normal by the time onion planting started this spring. This, together with rather cool spring conditions since early April (after a warm spell in late March), is expected to exacerbate problems with Rhizoctonia stunted patches in the sandier soils of the Columbia Basin, as research has shown that the larger are the cereal cover crop plants at the time the cover crop is killed with a herbicide application, the more severe the Rhizoctonia stunting tends to be.

 

Temperature Outlook* [next 2 – 4 weeks]:    Normal

Precipitation Outlook* [next 2 – 4 weeks]:    Normal to 30% below normal

*Courtesy of Planalytics, Inc.

 

Insect Scouting, Outlook and Management Last Modified: 04/24/13

Thrips

We have not seen many thrips yet.

Thrips damage on stored red onion bulbs was observed this past winter. Symptoms primarily consisted of speckling from feeding injury around the neck of the bulbs on the outer dry scales and one or two fleshy scales. Thrips were typically present between the dry scales and outermost fleshy scale.

 

Maggots

Seed corn maggot problems appear to be more frequent and severe than normal for this time of year. Increased seed corn maggot problems are probably due, in some part, to warmer soil temperatures in the early spring. Warmer soil temperatures will cause overwintering pupae to hatch and begin earlier mating and oviposition than when spring soil temperatures are cooler. The large size of cereal cover crops coming out of the winter, because of a relatively mild winter, has resulted in a lot of cover crop residue incorporated into the soil prior to planting onion bulb crops this spring, which is also attractive to the flies.

Other

No surveys or reports at this time.

 

Disease Scouting, Outlook and Management Last Modified: 04/24/13

Iris yellow spot virus

No reports at this time.

 

Soil-borne Diseases (Damping Off, Pink Root, Fusarium)

Rhizoctonia stunted patches have already been reported by several growers in the Walla Walla sweet onion production area as well as the southern Columbia Basin. See the comment above in the ‘Weather Impacts’ section. This disease is expected to be more severe than normal because of the mild winter resulting in larger plants in overwintered cereal cover crops that often are grown in rotation with onion bulb crops seeded in spring and serve as a ‘green bridge’ for infection of Rhizoctonia spp. from the cereal roots to onion seedling roots; and cool spring conditions that slow emergence and growth of onion seedlings, thereby increasing the window of susceptibility to infection by these Rhizoctonia spp.

 

Fungal Diseases (purple blotch, downy mildew, Botrytis)

No surveys or reports at this time.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots)

No surveys or reports at this time.

 

State Contact for Project
Lindsey du Toit
Associate Professor of Plant Pathology

Washington State University
Email: dutoit@wsu.edu

 

Collaborators: Jordan Eggers, Hanu Pappu, Brenda Schroeder, Tim Waters, Carrie Wohleb, Bill Dean

 

Lindsey du Toit – WA State Commentary – Onion ipmPIPE

onion_flowers

2012 WA Commentary 9-7-2012

WASHINGTON and OREGON Columbia Basin Onion Commentary

Onion Crop Growth Stage and Status Last Modified: 09/07/12

Many onion bulbs crops in the Columbia Basin are being undercut, windrowed, and harvested.

Later maturing crops will be harvested in late September-early October. Sentinel Plots in the

south Basin have either been harvested or undercut. Sentinel Plots in the north Basin are all at

tops down and close to undercutting.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 09/07/12

Weather has been seasonally warm and dry in late August-early September.

Central Washington temperature outlook (2-4 weeks): average to 30% above average*

Central Washington precipitation outlook (2-4 weeks): 40% below average*

* Courtesy of Planalytics, Inc. (http://apps.planalytics.com/aginsights/pipeweather.jsp)

 

Insect Scouting, Outlook and Management Last Modified: 09/07/12

Thrips: Thrips numbers in Sentinel Plots were not counted as plots have been harvested or

undercut, or will soon be undercut.

 

No other insect problems to report as the SPs have been harvested or are undercut or ready for

undercutting.

 

Disease Scouting, Outlook and Management Last Modified: 09/07/12

No further disease reports for the Sentinel Plots as the SPs have been harvested or are undercut

or ready for undercutting.

 

No disease reports from growers over the last two weeks, as harvest operations are in full swing

on most farms.

 

Onion Specialist (submitted on behalf of WA/north-central OR onion participants)

Lindsey du Toit

Associate Professor of Plant Pathology, Washington State University,

Email: dutoit@wsu.edu, 360-848-6140

 

Lindsey du Toit – WA State Commentary – Onion ipmPIPE

onion_flowers

2012 WA Commentary 8-24-2012

WASHINGTON and OREGON Columbia Basin Onion Commentary

 

Onion Crop Growth Stage and Status Last Modified: 08/24/12

Crops are at stage 8 in Sentinel Plots in the south and north Columbia Basin. The crops look good overall. Sentinel plots in the south Basin will be lifted next week, most likely. Fields in the north Basin with the Sentinel Plots received maleic hydrazide applications this week, and all three fields in the north Basin with SPs are starting to senesce (tops beginning to fall over).

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 08/24/12

Late July and the first half of August have been quite warm in the Columbia Basin (highs in the 90’s to 100’s F), typical for this time of year.

Central Washington temperature outlook (2-4 weeks): average*

Central Washington precipitation outlook (2-4 weeks): average to 30% below average*

* Courtesy of Planalytics, Inc. (http://apps.planalytics.com/aginsights/pipeweather.jsp)

 

Insect Scouting, Outlook and Management Last Modified: 08/24/12

Thrips: Thrips numbers in Sentinel Plots averaged 3-4/plant in the south Columbia Basin, and 2.8/plant in the north Basin, a continued decline since the last regional report.

 

Maggots: No maggot damage this time of year.

 

Other: Same as last regional report, with 4% of plants in one south Columbia Basin Sentinel Plot having leafminer injury, and 2% of the plants in that plot with green peach aphids. Leafminer damage overall seems worse than previous years in the south Basin. The SPs in all three north Basin fields have two-spotted spider mites, with quite a few in the Moses Lake SP.

 

Disease Scouting, Outlook and Management Last Modified: 08/24/12

Iris yellow spot virus: No symptoms in Sentinel Plots. No further reports from growers either.

 

Soil-borne Diseases (damping-off, pink root, Fusarium, Rhizoctonia): 2% of the plants in one Sentinel Plot in the south Columbia Basin are infected with pink root, as noted in the last report.

 

Fungal Diseases (purple blotch, downy mildew, Botrytis): Symptomatic Botrytis allii (or B. aclada) noted by a grower in south Columbia Basin, but no samples received for confirmation.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots): Symptoms of bacterial soft rot continue to be observed in some overhead irrigated bulb crops in the Columbia Basin, including in one of the Sentinel Plots (as noted in the last report).

 


Onion Specialist (submitted on behalf of WA/north-central OR onion participants)

Lindsey du Toit

Associate Professor of Plant Pathology, Washington State University,

Email: dutoit@wsu.edu, 360-848-6140

 

Lindsey du Toit – WA OR State Commentary – Onion ipmPIPE

onion_flowers

2012 WA Commentary 8-11-2012

WASHINGTON and OREGON Columbia Basin Onion Commentary

 

Onion Crop Growth Stage and Status Last Modified: 08/11/12

Crops are at stage 7 in Sentinel Plots in the south and north Columbia Basin. The crops look good overall. Undercutting, topping, field curing, and even harvest have begun for some spring-sown crops in the south Basin. Most onion seed crops have been swathed for harvest.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 08/11/12

Late July and the first half of August have been quite warm in the Columbia Basin (highs in the 90’s to 100’s F), typical for this time of year.

Central Washington temperature outlook (2-4 weeks): average to 30% above average*

Central Washington precipitation outlook (2-4 weeks): average (no rain for this region)*

* Courtesy of Planalytics, Inc. (http://apps.planalytics.com)

 

Insect Scouting, Outlook and Management Last Modified: 08/11/12

Thrips: Thrips numbers in Sentinel Plots averaged 7-12/plant in the south Columbia Basin, and 16-17/plant in the north Basin, a decline since the last regional report.

 

Maggots: No maggot damage to report this time of year.

 

Other: 4% of plants in one south Columbia Basin Sentinel Plot had leafminer injury, and 2% of the plants in that Sentinel Plot had green peach aphids.

 

Disease Scouting, Outlook and Management Last Modified: 08/11/12

Iris yellow spot virus: No symptoms in the Sentinel Plots. Not much to report from commercial crops either, although a few IYSV samples have been received at the Oregon State University Hermiston AREC.

 

Soil-borne Diseases (damping-off, pink root, Fusarium, Rhizoctonia): 2% of the plants in one Sentinel Plot in the south Columbia Basin are infected with pink root.

 

Fungal Diseases (purple blotch, downy mildew, Botrytis): No further incidences since the last regional report.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots): Symptoms of bacterial soft rot were observed in several overhead irrigated bulb crops in the Columbia Basin at a wide range of incidences, including at 1% in one of the Sentinel Plots in the south Basin. Frequent rain events and occasional hail storms in mid-July may have exacerbated bacterial infections.

 


Onion Specialist (submitted on behalf of WA/north-central OR onion participants)

Lindsey du Toit
Associate Professor of Plant Pathology, Washington State University,

Email: dutoit@wsu.edu, 360-848-6140

 

Lindsey du Toit -Washington State Commentary – Onion ipmPIPE

onion_flowers

2012 WA Commentary 7-27-2012

 

WASHINGTON and OREGON Columbia Basin Onion Commentary

 

Onion Crop Growth Stage and Status Last Modified: 07/27/12

Crops are at stages 6-7 in Sentinel Plots in the south and north Columbia Basin. The crops look good overall. Some onion seed crops have been swathed and are drying, while others are still in pollination and seed set.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 07/27/12

July has been hot and surprisingly humid for the Columbia Basin, with frequent thunderstorms. Scattered hailstorms in mid-July resulted in damage to >1,000 acres of onion bulb crops and some onion seed crops. Growers are concerned about secondary infection from bacteria and fungi in hail-damaged crops.

Central Washington temperature outlook (2-4 weeks): 30% above average*

Central Washington precipitation outlook (2-4 weeks): 40% below normal*

* Courtesy of Planalytics, Inc. (http://apps.planalytics.com)

 

Insect Scouting, Outlook and Management Last Modified: 07/27/12

Thrips

Thrips numbers averaged 12-13/plant in the south Columbia Basin Sentinel Plots, and 24-48/plant in Sentinel Plots in the north Basin.

Maggots

No maggot damage this time of year.

 

Other

4% of plants in one of the south Columbia Basin Sentinel Plots had leafminer injury, and 2% of the plants in that Sentinel Plot had green peach aphids.

 

Disease Scouting, Outlook and Management Last Modified: 07/27/12

Iris yellow spot virus

No symptoms in Sentinel Plots.

Soil-borne Diseases (damping-off, pink root, Fusarium, Rhizoctonia)

Pink root observed on 2% of plants in one of the south Basin Sentinel Plots.

 

Fungal Diseases (purple blotch, downy mildew, Botrytis)

Downy mildew observed in several bulb crops in the south Columbia Basin. A drip-irrigated onion bulb crop in the south Basin had symptoms of Botrytis infection in the bulbs, apparently associated with excessive irrigation.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots)

Soft rot was not observed in any Sentinel Plots, but secondary bacterial infection was observed on lower scapes in several onion seed crops with hail damage in the north Columbia Basin, with girdling lesions caused by secondary bacterial infections observed on the lower end of scapes (<5%). Similarly, with >1,000 acres of bulb crops damaged by hail in mid-July, some growers are concerned about secondary bacterial infection in bulb crops.

 


Onion Specialist (submitted on behalf of WA/north-central OR onion participants)

Lindsey du Toit
Associate Professor of Plant Pathology, Washington State University,

Email: dutoit@wsu.edu, 360-848-6140

 

Lindsey du Toit – Washington State Commentary – Onion ipmPIPE

onion_flowers

2012 WA Commentary 7-13-2012

 

WASHINGTON and OREGON Columbia Basin Onion Commentary

 

Onion Crop Growth Stage and Status Last Modified: 07/13/12

Overwintered onion crops in the south Columbia Basin are still being harvested. Spring planted onion bulb crops look good overall. Crops are at stages 5-7 in the south Columbia Basin, and 5-6 in the north Columbia Basin in the Sentinel Plots. The crop looks good overall. If thrips numbers continue to go down in the south Basin, that will be good news, but we may not be out of the woods yet for thrips problems.

 

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 07/13/12

June in central WA turned out to be even cooler than in 2011, surprisingly, with unusually high precipitation and even hail. Early July turned hot and dry.

Central Washington temperature outlook (2-4 weeks): normal to 30% above average*

Central Washington precipitation outlook (2-4 weeks): normal*

* Courtesy of Planalytics, Inc. (http://apps.planalytics.com)

 

Insect Scouting, Outlook and Management Last Modified: 07/13/12

Thrips

Thrips numbers have actually gone down a bit in parts of central WA. Onion plants may be sending more resources to the bulb, and leaf growth is slowed, which seems to naturally decrease or reduce thrips fecundity.

Thrips numbers in the north Columbia Basin are either similar or greater than two weeks ago (8 to 40 thrips/plant).

Maggots

No maggot damage to report this time of year.

 

Other

Some leaf miners and a few aphids were detected in one of the Sentinel Plots in the south Basin.

 

Disease Scouting, Outlook and Management Last Modified: 07/13/12

Iris yellow spot virus

Nothing significant to report. No symptoms in Sentinel Plots.

Soil-borne Diseases (damping-off, pink root, Fusarium, Rhizoctonia)

Some severe patches of stunted plants observed from Rhizoctonia infection in bulb crops on sandy fields in the north Basin, planted in rotation with overwintering cereal cover crops that were killed with herbicides at the time of planting onion seed. No patches in Sentinel Plots.

 

Fungal Diseases (purple blotch, downy mildew, Botrytis)

Additional pink root samples observed in some fields in the north Columbia Basin, particularly some fields rotated regularly with sweet corn and onion.

 

Bacterial Diseases (Xanthomonas, center rot, soft rots)

Soft rot observed at a low incidence in a bulb crop under center pivot irrigation (5/1,000 plants examined), but not in the Sentinel Plots.

 


Onion Specialist (submitted on behalf of WA/north-central OR onion participants)

Lindsey du Toit
Associate Professor of Plant Pathology, Washington State University,

Email: dutoit@wsu.edu, 360-848-6140