June 23, 2017

Howard Schwartz – CO State Commentary – Onion ipmPIPE

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CO Commentary (09-07-12)

 

COLORADO Commentary

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

Thrips pressure is dropping off as plants mature in Eastern, Southern and Western Regions of the state. Risk Models show that Thrips and IYSV are at Mium to High Risk, while foliar bacterial and fungal threats remain at Medium Risk in most regions due to persistent high temperatures and low moisture conditions.

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

Most regions of the state received little or no rain in the last week. Temperatures have averaged in the mid 80s to low 90s during the day, and mid 50s to low 60s in the evening.

Temperature Outlook* [2 – 4 weeks]: Normal

Precipitation Outlook* [2 – 4 weeks]: Normal

*Courtesy of Planalytics, Inc.

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

Thrips – Populations declining in most fields as plants approach maturity.

Maggots – No reports at this time Other – No other reports at this time.

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

Iris yellow spot virus – IYSV detected in surveys of seeded onions (trace to more than 75%) sampled in northern and southern regions.

Soil-borne Diseases (Damping Off, Pink Root, Fusarium) – Pink Root and Fusarium basal rot incidence light to moderate in affected fields throughout the state.

Fungal Diseases (purple blotch, downy mildew, Botrytis) – No reports at this time. Late-season fungicide protection of foliage and necks is recommended for storage rot control; combined with good curing of onions in the field and storage.

Bacterial Diseases (Xanthomonas, center rot, soft rots) – Surveys from all regions detected trace soft rot and leaf blight infections. Late-season bactericide protection of foliage and necks is recommended for storage rot control; combined with good curing of onions in the field and storage.

State Contact for Project Howard Schwartz Professor of Plant Pathology Colorado State University Email:howard.schwartz@colostate.edu

Collaborators: Whitney Cranshaw, Ned Tisserat, Stephanie Szostek, Janet Hardin,

Mike Bartolo, Thad Gourd, Bob Hammon, Colorado Onion Association

Mary Hausbeck – Michigan State Commentary – Onion ipmPIPE

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2012_08_10_Michigan_ipmOnion_Report [7]

MICHIGAN Commentary
Onion Crop Growth Stage and Status Last Modified: 08/10/12
Vegetative phase of most onions have nearly reached the end as the outer leaves have continued to dry out. Some early varieties have started to top over.

Weather Impacts (temperature, rain, hail, freezing) Last Modified: 08/10/12
Several events of scattered rain have occurred. Total rainfall in past two weeks across the monitored sites was generally between 0.72 and 1.32 inches. Temperatures in the northern sites were high from 69 to 93F and low from 54 to 71F, while temperatures in the southern sites were high from 72 to 95F and low from 49 to 71F.

Insect Scouting, Outlook and Management Last Modified: 08/10/12
Thrips
Average thrips numbers were low in some areas with one to two per plant since as an insecticide was sprayed a few day prior to the scouting. However, thrips numbers in one field located in the northern site was high with 19 per plant.
Maggots
None found in surveys or reported at this time.
Other
None found in surveys or reported at this time.

Disease Scouting, Outlook and Management Last Modified: 08/10/12
Iris yellow spot virus
Iris yellow spot virus was found in a site reported previously with the incidence appearing to increase; more diseased plant have been detected.

Soil-borne Diseases (Damping Off, Pink Root, Fusarium)
Smut has been identified in more mature plants showing dark spores forming in the leaf whorl and scale tissues. The dieback of the foliage as a result is obvious.
High incidence of pink root has been found in nearly of all the scouted fields. Aboveground symptoms show the dieback of the leaf tips. Small bulbs have formed on these stunted plants. Below ground symptoms indicate severe infection and damage to nearly the entire root system.

Fungal Diseases (purple blotch, downy mildew, Botrytis)
Stemphylium leaf blight was prevalent in many sentinel plots, while other foliar diseases including purple blotch and anthracnose have been found at low incidence.

Bacterial Diseases (Xanthomonas, center rot, soft rots)
Stalk and leaf necrosis (or leaf blight and bulb rot) caused by Pantoea agglomerans has been recently detected at a damage level of 2 out of 5 (~8%) in a field at the southern site. Symptoms include blighting and withering on the leaves. In addition, infected leaves appear to be watersoaked.

Onion Specialist Mary Hausbeck Professor and Extension Specialist Michigan State University Email:hausbec1@msu.edu