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2021 Peach Leaf Curl Delayed-Dormant Spring Application
General Landscape and Garden Treasure Valley
Peach leaf curl (Taphrina deformans)
Posted on: February 6, 2021 by Nic Usabel
If you experienced peach leaf curl on peach or nectarine trees during the 2020 growing season and did not treat in the fall a delayed-dormant application before floral buds open is recommended to help with control.
DESCRIPTION: Peach leaf curl caused by fungus Taphrina deformans and is specific to peaches and nectarines. Trees that are infected will have leaves that are distorted or curl, appear blistered, and develop a yellow or red color.
CONTROL: Spray with an approved fungicide such as lime sulfur or copper-based fungicide. More chemical options listed by viewing the PNW handbook link below. Apply according to label directions and instructions. Cultural control for backyard growers includes removal of infected leaves that have fallen and selecting resistant cultivars.
If you have additional questions, contact your local University of Idaho Extension office at https://www.extension.uidaho.edu/find.aspx.
» https://pnwhandbooks.org/plantdisease/host-disease/peach-prunus-persica-leaf-curl
2021 Pruning Deciduous Trees & Shrubs
General Landscape and Garden Treasure Valley
Posted on: January 30, 2021 by Nic Usabel
It is time to prune deciduous trees (landscape & fruit) and shrubs. As a general guide remove no more than one-third of the tree when pruning. Reference the first and third link for pruning deciduous trees and for a video reference the fourth link. Reference the second link for fruit trees.
Prune shrub species which grow on the current season’s growth during the dormant period, usually late winter early spring. A few examples of flowering shrubs in this grouping including butterfly bush, heather, heavenly bamboo, hydrangea, shrubby roses and rose of sharon. Reference the third link for more information.
For shrub species which form buds on last season’s growth prune these species within about two months after the flowers fade. On these species, flower buds form in late summer and early fall. Winter pruning decreases the number of flowers the following spring as branches containing flower buds are removed. A few examples of flowering shrubs in this grouping include azaleas, lilac, magnolia, mockorange, serviceberry, and witchhazel. Reference the third link for more information.
For most areas of Idaho, plants that bloom before June 1 formed the flowers the previous year on old wood. Those that bloom after June 1 form flowers on new growth. Keep in mind that this is only a rough guideline.
For classes on pruning in the Treasure Valley see the attached file.
If you have additional questions, contact your local UI Extension office. To search by county visit https://www.extension.uidaho.edu/find.aspx
» https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1139-2015.pdf
» https://catalog.extension.oregonstate.edu/pnw400/html
» https://www.extension.purdue.edu/extmedia/HO/HO-4-W.pdf
2021 Delayed-Dormant Oil Application
General Landscape and Garden Treasure Valley
Posted on: January 30, 2021 by Nic Usabel
The use of horticultural oil as a dormant spray can target many insect pests at a time when beneficial insects are not yet active. Even though we refer to it as dormant oil, the application is not when trees are still dormant. A better term is a delayed-dormant application because the oil should be applied after bud swell. This coincides with the increasing activity of the overwintering insect stages, such as aphid eggs, scale nymphs, and peach twig borer larvae.
WHEN TO SPRAY: Two factors must correspond – temperature and bud stage.
TEMPERATURE: Only apply oil if temperatures remain above 40°F for 24 hours after application. With ideal conditions oil should be applied on a clear, non-windy day in the 50 to 70°F temperature range.
BUD STAGE: The window of application extends from bud swell to when the leaves just start emerging. The last point you can safely apply oil based on fruit tree crop are Apple: Half-inch green, but ideal application at green tip stage. Pear: Cluster bud. Cherry: White bud. Peach/nectarine: pre-bloom. Refer to the first link below for pictures of bud stage.
Oil should be applied at a rate of 2% (5 Tbs in 1 gallon water) and thoroughly cover all cracks and crevices. If aphids and scale have been a serious problem in previous years an insecticide could be added, see second link for chemical products listed by pest. Read and follow label instructions for preparation and application.
If you have additional questions, contact your local UI Extension office. Reference the third link to search by county.
» https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1643&context=extension_curall
» https://www.extension.uidaho.edu/find.aspx
» https://extension.colostate.edu/topic-areas/insects/insect-control-horticultural-oils-5-569/
2021 Miller Research Potato Disease Management Seminars
Potato All Locations
Posted on: January 28, 2021 by Jeff Miller
Due to the COVID-19 pandemic, Miller Research will not be holding its annual Potato Pest Management Meeting. Instead, we will be having four 1-hour virtual seminars where we will discuss four different topics related to potato disease management. One CCA (integrated pest management) credit and one ISDA pesticide recertification credit have been awarded for each session. You will be required to answer some participation questions in order to get the ISDA credit. Each session will run from 12:00 noon to 1:00 pm. Registration is free.
Meetings will be held by Zoom and registration is required separately for each session. To register for each session, click on the link. You will be taken to a page where you need to enter your name and email address. After successfully registering, you will receive a confirmation email that contains the link to log into the session.
Pre-License Online Training
All Crops All Locations
Posted on: January 27, 2021 by Jerry Neufeld
The University of Idaho will be conducting an online Pre-License Training for those people wanting to receive training prior to taking the examinations for a pesticide applicator license. Click on the pdf below for more information.
2021 Virtual Bean School
Dry Beans All Locations
Posted on: January 12, 2021 by Jerry Neufeld
The 2021 Treasure Valley and Magic Valley Bean Schools will be virtual this year. The Bean School will be held January 27 and 28 in the morning. There will be 2 Idaho pesticide licenses credits available. Click on the pdf below for more information.
Idaho and Eastern Oregon Onion Crop Protection Zoom Meeting
All Crops All Locations
Posted on: January 6, 2021 by Jerry Neufeld
The Idaho and Eastern Oregon Onion Crop Protection Meeting will be on Zoom this year. It will be held Tuesday, February 2nd from 9 am to 12 pm. Click on the pdf below for the link and more information. There will be one Idaho license credit.
» Idaho_Eastern_Oregon_Onion_Crop_Protection_Meeting_agenda.pdf
Virtual Idaho Potato Conference January 19-21, 2021
Potato All Locations
Idaho Potato Conference
Posted on: January 4, 2021 by Nora Olsen
Registration is open! Plan to attend the 53rd annual Idaho Potato Conference January 19-21, 2021. Given the unusual times of a global pandemic, the Idaho Potato Conference shifted from the annual in-person conference held in Pocatello to three days of virtual presentations. The 20-minute pre-recorded presentations with an additional 5 minutes of live Q and A will be given throughout the morning of each day (8 am to noon MT). In addition, 5-minute updates by leading potato industry companies will be included each day.
Spanish Language Session will also be offered virtually for 2021. This session will be held from 1 to 3 pm on January 19th. Topics in Spanish will include reducing bruise, grading potatoes, common storage disease and much more. There will be short videos and live discussions led by University of Idaho extension educators Joseph Sagers and Jason Thomas.
Highlights for this year’s three-day virtual conference include:
• The virtual format allows us to invite many of our colleagues from outside of Idaho. We are pleased to have
o Dr. Paul Bethke from USDA-ARS in Wisconsin to discuss “Tuber lenticels”— what is their function and why do they become enlarged?
o Dr. Andy Robinson from North Dakota University/University of Minnesota – to elaborate on the seasonal topic of “Managing brown center and hollow heart”
o Dr. Ken Frost from Oregon State University will provide a much-needed summary on the “Blackleg/soft rot disease in potatoes”
o Dr. Mark Pavek from Washington State University will provide “Cultural management updates on Clearwater Russet and Alturas” and his graduate student Francisco Gonzalez will provide new (and old) information on “Measuring soil moisture in potato fields”
• The remainder of the 20-minute presentations will focus on a wide variety of topics:
o Changes in potato quality during packing and shipping
o Factors that impact development of bruises
o Analyzing the annual Idaho potato price change during crop transition
o What makes new varieties better than Burbank?
o Susceptibility of russet cultivars to common potato diseases
o Learning to use growth regulators
o Managing early die in potatoes
o Best management practices for pink rot and Pythium leak
o Soil-borne diseases – what causes them and what you can do about it
o Potato Mop Top virus (PMTV) and other viruses
o Diagnosing and predicting foliar diseases in Idaho
o What happened to Zebra Chip in ID?
o Variety reaction to Zebra Chip and interaction with PVY
o Volunteer potato control
o Using plant-pest interactions to build resistance
o What does healthy soil look like in Southern Idaho?
o Sustainability and the potato industry: working together to meet customer and consumer demands
o Idaho Potato Commission update
Idaho Pesticide License Recertification credits (3) will be available on January 20th. Attendees are required by ISDA to pass a short on-line quiz to receive credits.
Registration is free, but you must register in advance—including the Spanish language session. Additional details regarding the agenda, topics, and registration can be found at the conference website www.uidaho.edu/cals/potatoes/news/idaho-potato-conference.
» https://www.uidaho.edu/cals/potatoes/news/idaho-potato-conference
PNWPestAlert.net surveys
Announcements All Locations
Posted on: December 21, 2020 by Jerry Neufeld
Thanks to everyone that completed a 2020 PestAlert.net survey. Mia, Cody and Tom were randomly selected for the Amazon gift cards. They will be put in the mail today.
2020 Protecting Trees from Sunscald
General Landscape and Garden Treasure Valley
Posted on: November 18, 2020 by Nic Usabel
Sunscald or southwest winter injury happens during the winter. Intense direct and reflected sunlight will activate tissues under the bark. At night, temperatures fall, and cells freeze, causing cell death. This damage is often not noticed for a few years until the bark has split open exposing the damage below. The damaged sites are prone to attack by wood-boring insects and fungal pathogens.
Recently planted trees, young trees, and trees with thin bark are more susceptible to sunscald. Trees species which are susceptible include maple, linden, mountain-ash, honeylocust, birch, walnut, crabapple, flowering cherry, fruit trees, aspen, ash, tuliptree, and willow.
To prevent sunscald damage from occurring keep the lower trunk insulated or shaded in winter. Susceptible trees can be protected by wrapping the trunk with paper tree wrap, overlapping about 33 percent with each turn. Wrap trunks upward from the base of the tree to a point just above the lowest branch. Wrap should be removed in early spring after the risk of a hard frost has passed. If not removed the wraps can harbor insects and disease. Trunks can also be protected by placing a light-colored board to the south and west of the tree trunk. In large applications white latex paint can be diluted 1:1 with water and applied on the southwest side of the lower trunk. Landscape design and planting susceptible trees to the north and east of buildings or evergreens can help to shade the lower trunk.
Have you completed the annual survey for the Landscape & Garden section of the PNW Pest Alert Network? Complete the survey by November 20th to be entered into a drawing for an Amazon gift card. See link 3 below to access the survey.
» http://pubs.cahnrs.wsu.edu/publications/wp-content/uploads/sites/2/publications/fs197e.pdf
» https://uidaho.co1.qualtrics.com/jfe/form/SV_3KvC6BV1KQ4zSPr
2020 Fall Control for Coryneum Blight & Peach Leaf Curl
General Landscape and Garden Treasure Valley
Coryneum blight (Thyrostroma carpophilum) & Peach leaf curl (Taphrina deformans)
Posted on: October 28, 2020 by Nic Usabel
Coryneum blight or commonly known as shothole disease which is caused by fungus Thyrostroma carpophilum. Trees which have been affected develop small, round, tan-to-purpleish spots which then dry and fall out of the leaf producing a shothole effect. Most cultivars of peach, nectarine, apricot, and almond are very susceptible while cherry and plum are less susceptible. In addition, ornamental plant species can show damage. Beyond the leaf, symptoms can also be seen on the current season and 1-year old fruiting wood. Infections consist of round, reddish spots which are slightly sunken.
Chemical control will occur at 50% leaf drop in late autumn by spraying with a copper-based fungicide, chlorothalonil, or Bordeaux mixture. Follow the label instructions for rate and application procedure. Prune out affected twigs when practical. Culturally control shothole disease by not allowing irrigation sprinklers to wet the tree foliage, select cultivars which are disease resistant when available, and remove and dispose of affected foliage and twigs.
Peach leaf curl caused by fungus Taphrina deformans and is specific to peaches and nectarines. Trees that are infected will have leaves that are distorted or curl, appear blistered, and develop a yellow or red color.
Control can be achieved by a single fungicide application in the fall after 90% of the leaves have fallen. Chemicals used for control are copper products or chlorothalonil. Follow the label instructions for rate and application procedure. Homeowners should also remove and dispose of infected leaves that have fallen to the ground, to remove as much inoculum as possible. Resistant varieties can be selected for additional cultural control.
» https://pnwhandbooks.org/plantdisease/host-disease/peach-prunus-persica-leaf-curl
» https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1736&context=extension_curall
» https://pnwhandbooks.org/plantdisease/host-disease/peach-prunus-persica-shothole
» http://ipm.ucanr.edu/PMG/GARDEN/FRUIT/DISEASE/shothole.html
2020 Idaho Association of Plant Protection Annual Meeting update
All Crops All Locations
Posted on: October 28, 2020 by Jeff Miller
With the current situation regarding COVID-19, the Idaho Association of Plant Protection has decided to not hold an in-person meeting in 2020. Instead, we will meet virtually using Zoom. There will be no cost to participate in the meeting.
The program will run from 1:00 PM to 5:00 PM on Wednesday, November 4, and 8:00 AM to 12:00 PM on Thursday, November 5. A total of 7.5 Certified Crop Advisor (CCA) and 7 ISDA Pesticide Recertification credits (ISDA) are available. Participants wishing to get ISDA credits will need to pass an online test as a way to verify attendance.
Information on the agenda and how to register can be found in the attached flier and link.
» https://millerresearch.com/event/2020-idaho-association-of-plant-protection-annual-meeting/
2020 Frost Alert
General Landscape and Garden Treasure Valley
Posted on: October 14, 2020 by Nic Usabel
Many locations across the Treasure Valley could experience a frost this evening. To review more details about frost tolerance for common vegetables view the first link below. To understand more about cold weather and frost protection reference the second link.
Have you enjoyed landscape and garden insect pest alerts this season? If so, consider donating to the “2C Master Gardener: Growing Skills & Expertise for Local Outreach” crowdfunding campaign by clicking the third link. Master Gardener volunteers in Canyon County help to monitor and report insect pests to the PNW Pest Alert Network. A donation of $5 will help maintain one trapping station for the upcoming year.
» https://extension.sdstate.edu/fall-frost-tolerance-common-vegetables
» https://extension.arizona.edu/sites/extension.arizona.edu/files/pubs/az1002.pdf
Armyworm damage in eastern Idaho wheat fields
Small Grains Eastern Idaho
armyworm
Posted on: October 6, 2020 by Jerry Neufeld
The following information is provided by Dr. Arash Rashed, Associate Professor, Department of Entomology, Plant Pathology and Nematology at the University of Idaho.
There have been reports of fall armyworm damage in some wheat fields between American Falls and Firth in eastern Idaho. Please inspect your fields as managing this pest is more effective during the early stages of development. Fall Armyworms are active during dark, so field inspections need to be done with a flashlight after sunset. They have a wide host range but prefer grasses; at this time of the year, wheat, barley, alfalfa, volunteers, and pasture are examples of crops that can host fall armyworms. They feed on foliar tissue and can consume young seedlings to the ground. During the day they hide in plant litter and/or just below the soil surface. There are no set thresholds and management recommendations depend on the stages of plant and larval development and the extent of the damage. More than 2-3 larger larvae (> 1/2in) per square foot may require control. Scout as many spots as possible within a field. Damage by fall armyworm is usually patchy and spot insecticide treatment is a possibility, where needed. Larvae cannot survive freezing temperatures and are also susceptible to diseases caused by entomopathogens at high densities.
For other closely related species and damage, you can visit pages 493-499 of the publication in the first link below:
You can also learn more about this pest from the PNW Insect Management Handbook in the second link below:
» http://pubs.cahnrs.wsu.edu/wp-content/uploads/sites/2/2017/06/em108-ch11.pdf
» https://pnwhandbooks.org/insect/agronomic/small-grain/small-grain-cutworm-armyworm
2020 Idaho Master Gardener Programs in the Treasure Valley
General Landscape and Garden Treasure Valley
Posted on: September 25, 2020 by Nic Usabel
Interested in becoming an Idaho Master Gardener. See below for program information coming near you.
UI Extension, Ada County (Boise, ID): Currently has waiting list for class. Additional information can be found at uidaho.edu/ada or by calling 208-287-5900.
UI Extension, Canyon County (Caldwell, ID): This location serves Canyon and Owyhee counties. Class to meet weekly Wednesday morning from 9am - noon January – April. Registration to open October 1st. Additional information can be found at uidaho.edu/canyon or by calling 208-459-6003.
UI Extension, Elmore County (Mountain Home, ID): Class to meet weekly Saturday from 10am – 2pm January – April. Registration open now. Additional information can be found at uidaho.edu/elmore or by calling 208-587-2136 ext. 1250
UI Extension, Washington County (Weiser, ID): This location serves the Payette River Valley (Gem, Payette, Washington, Adams counties). Additional information can be found at uidaho.edu/Washington or by calling 208-414-0415.
Don’t see your county listed? Use the link below to find all program options in Idaho.
2020 Brown Marmorated Stink Bug
General Landscape and Garden Treasure Valley
Brown Marmorated Stink Bug (Halyomorpha halys)
Posted on: September 23, 2020 by Nic Usabel
The Brown Marmorated Stink Bug (BMSB) is an invasive insect pest from eastern Asia. Its first North America detection was in Pennsylvania in 1996. BMSB adults were first discovered in Canyon County in May 2012 and in Ada County in October 2014. This year a location with traps adjacent to orchards in Canyon and Payette counties participating in the SCRI nationwide survey has collected five (5) BMSB in two subsequent weeks.
If you believe you have found BMSB in Idaho take a specimen to your local Extension office or contact the Idaho State Department of Agriculture’s Pest Survey Program at (208) 332-8627.
BMSB has a shield-shaped body with mottled brownish-grey coloration. The adults are just over ½ inch long, and their antennae are marked with distinctive white bands. The insect’s underside is white with gray or black markings, and its legs are brown with faint white banding. Unlike most native stink bugs, BMSB has smooth “shoulders”. BMSBs have distinctive black and white “skirting” around their abdomens that protrudes from under the wings. See image.
BMSB has a broad host range that includes fruit, vegetable, ornamental, and field crop plants. The insect has a mouthpart for piercing and sucking plant sap and prefers fruits and seeds pods (reproductive structures). In Utah, the catalpa tree has shown the greatest numbers during detection and assessment of invasion risk.
» https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2785&context=extension_curall
Lso results delayed
Potato All Locations
Potato Psyllid
Posted on: September 17, 2020 by Lucy Standley
Last week’s Lso results are delayed because of the shutdown of main campus buildings due to wildfire smoke. We expect to post the results to our website by the end of next week. Sorry for any inconvenience.
More information can be found here: http://www.uidaho.edu/cals/potatoes/news
--Click on the links under “Updated weekly reports” for details on trap captures.
--Click on the “Psyllid Management” link on the left panel for information on psyllid and zebra chip biology and management.
University of Idaho Pesticide Recertification Webinar Series, Fall 2020
All Crops All Locations
Posted on: September 15, 2020 by Jerry Neufeld
The University of Idaho Pesticide Recertification trainings will not be the same this fall as they have been in the past years. In many cases, if not all, in person training will not be offered. However, you will still be able to get the credits needed for your license. Click on the pdf below for information on how to get license credits through the University of Idaho Pesticide Recertification Webinar Series.
Fall 2020 ISDA Pesticide Disposal Program
All Crops All Locations
Posted on: September 15, 2020 by Jerry Neufeld
The Idaho State Department of Agriculture has released their schedule for the fall 2020, Pesticide Disposal Program. Click on the pdf below for all the details.
2020 Master Gardener Fall Perennial Plant Sale
General Landscape and Garden Treasure Valley
Posted on: September 11, 2020 by Nic Usabel
Canyon County Master Gardeners are holding a Fall Perennial Plant Sale. Orders can be placed online now, see first link below, and picked up curbside Saturday, September 19th from 9 AM – Noon at the UI Extension, Canyon County location at 501 Main St. Caldwell, ID 83605.
For additional information reference the flyer link below or call UI Extension, Canyon County at 208-459-6003.
Final psyllid trap capture report for the 2020 season
Potato All Locations
potato psyllid
Posted on: September 10, 2020 by Erik Wenninger
This week we had traps deployed in 45 of the 65 fields (69%) monitored this year; 20 fields had been vine killed and were not monitored. We found a total of 105 psyllids across 16 (35%) of the 45 fields.
Psyllids were collected on sticky traps in potato in the following counties: Canyon (5 fields), Owyhee (1 field), Elmore (4 fields), Twin Falls (5 fields), and Power (1 field).
From last week’s samples, no psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC).
We are not including “heat maps” this week given that they tend to show skewed patterns with smaller sample sizes.
This week concludes our 2020 psyllid monitoring program, following recommendations from our ZC Advisory Committee of shortening the duration. However, we will report on the last set of Lso results next week.
Total psyllid captures are still down from two weeks ago and based on previous years’ observations we would expect their numbers to continue to reduce; however, psyllids likely will continue dispersing among the remaining fields as vine kill continues. Overall captures of psyllids this season were higher than the last two seasons, though still nowhere near as high as the “epic” years of 2016 and 2012. Thus far, we have also seen our lowest incidence of Lso-positive psyllids yet (0.4%). Together, we expect that the modest psyllid abundance and very low Lso incidence this year should result in relatively low incidence of ZC in harvested tubers. But remember that, at least in our experiments with Russet Burbank, some risk of ZC remains if infection occurs within 1-2 weeks before vine kill.
More information can be found here: http://www.uidaho.edu/cals/potatoes/news
--Click on the links under “Updated weekly reports” for details on trap captures.
--Click on the “Psyllid Management” link on the left panel for information on psyllid and zebra chip biology and management.
2020 Fall Lawn Fertilization & Care
General Landscape and Garden Treasure Valley
Posted on: September 10, 2020 by Nic Usabel
For lawns, University of Idaho turf specialists recommend splitting fertilizer into three (3) applications early May, early September, and later October/November. Reference the publications linked below to identify fertilization amounts using soil test results (first publication link) or general recommendations for southern Idaho (second publication link). Apply fertilizer following label directions.
If your lawn is suffering from soil compaction or development of a thick thatch layer fall is the optimal time to core aerate. For more information on core aeration reference the third publication link below.
Fall is a great time to control perennial weeds in the landscape if opting to use herbicides. Perennials will begin storing carbohydrates in the roots promoting herbicides to be drawn deeper into the root system and allowing for better control.
If there are additional questions on lawn care or weed management reach out to a local University of Idaho Extension office.
» https://www.extension.uidaho.edu/publishing/pdf/CIS/CIS1182.pdf
» https://www.extension.uidaho.edu/publishing/pdf/CIS/CIS0846.pdf
2020 Reduce Watering Frequency During Fall
General Landscape and Garden Treasure Valley
Posted on: September 9, 2020 by Nic Usabel
The days are shortening, and evening temperatures are cooling. Now is the time to adjust the frequency between irrigation days for the landscape and garden.
Lawn irrigation systems should be set to increase the number of days between irrigation according to soil texture. Adjusting the frequency of watering versus the run time allows for replenishment of the water holding capacity and usable water in the soil profile (see publication link one or two below). This deep and infrequent method encourages deeper root growth of plants.
Also consider a deep watering for trees and shrubs at the drip line (see third publication link) prior to irrigation water being turned off. Evergreen trees and shrubs will continue to lose moisture from their needles or leaves all winter long.
» https://www.extension.uidaho.edu/publishing/pdf/CIS/CIS1098.pdf
» https://www.extension.uidaho.edu/publishing/pdf/CIS/CIS1157.pdf
September 3, 2020 Psyllid Monitoring Update
Potato All Locations
Potato Psyllid
Posted on: September 3, 2020 by Lucy Standley
This week we had traps deployed in 48 of the 65 fields (73%) monitored this year; 17 fields have been vine killed and will no longer be monitored. We found a total of 92 psyllids across 18 (37%) of the 48 fields.
Psyllids were collected on sticky traps in potato in the following counties: Canyon (7 fields), Owyhee (1 field), Elmore (4 fields), Twin Falls (4 fields), and Power (2 fields).
From last week’s samples, no psyllids tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). However, due to shipping delays from last week, a few Lso results will be delayed until next week.
We are not including “heat maps” this week given that they tend to show skewed patterns with smaller sample sizes.
Total psyllid captures were down considerably this week, which was related to fewer fields being monitored but also fewer captures in most of the remaining fields. It appears that we saw peak seasonal captures last week. However, remember that, at least in our experiments with Russet Burbank, some risk of ZC remains if infection occurs within 1-2 weeks before vine kill.
More information can be found here: http://www.uidaho.edu/cals/potatoes/news
--Click on the links under “Updated weekly reports” for details on trap captures.
--Click on the “Psyllid Management” link on the left panel for information on psyllid and zebra chip biology and management.
August 28, 2020 First Lso-positive psyllid found in Canyon County
Potato All Locations
Potato Psyllid
Posted on: August 28, 2020 by Lucy Standley
This week we had traps deployed in 60 of the 65 fields (92%) monitored this year; five fields have been vine killed and will no longer be monitored. We found a total of 199 psyllids across 35 (58%) of the 60 fields.
Psyllids were collected on sticky traps in potato in the following counties: Payette (1 field), Canyon (12 fields), Owyhee (2 fields), Gem (1 field), Elmore (5 fields), Gooding (1 field), Jerome (4 fields), Twin Falls (6 fields), and Power (3 field).
From last week’s samples, one psyllid (collected in Canyon County) tested positive for Lso (liberibacter), the bacterium associated with zebra chip disease (ZC). However, due to shipping delays from last week, a few Lso results will be delayed until next week.
“Heat maps” of this week’s results are included on the UI and WSU websites (see links below). “Heat maps” describe predicted psyllid densities across the landscape, based on our trap counts and on predictive models developed over six years of psyllid monitoring in Idaho. The heat maps graphically reflect the relatively high abundance of psyllids collected in some fields in Canyon and Twin Falls counties.
Total psyllid captures were the highest we have observed this year, which is not surprising given that captures typically increase toward the end of the season, likely in part due to increase dispersal in relation to senescence and vine kill. We continue to urge growers to maintain their IPM programs. Tubers may still be at high risk of ZC if infection occurs 3 or more weeks before vine kill; in our experiments with Russet Burbank, risk diminishes within 1-2 weeks before vine kill but does not disappear.
More information can be found here: http://www.uidaho.edu/cals/potatoes/news
--Click on the links under “Updated weekly reports” for details on trap captures.
--Click on the “Psyllid Management” link on the left panel for information on psyllid and zebra chip biology and management.
» http://www.uidaho.edu/cals/potatoes/news
