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Landscape & Garden Alerts

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2021 Leafminer in Leafy Greens

General Landscape and Garden    Treasure Valley

Leafminer (Liriomyza spp.)

Posted on: May 21, 2021 by Nic Usabel

Canyon County Idaho Master Gardeners have spotted leafminer damage on a recent Integrated Pest Management walk.

The leafminer (Liriomyza spp.) can be destructive to beets, spinach, chard, and other leafy greens. Leafminer describes the larval stage of various insects but are most commonly those that feed on vegetables. The adults are small black to gray flies with yellow markings in order Diptera.

Leafminer larvae form visible tunnels (mines) as they feed within the leaf tissue affecting the market value of vegetables harvested for edible foliage. Larvae are nearly translucent white or yellow color and about 0.25 inch long when mature.

To control regularly check leaves for mines which are sometimes more visible on the underside. For home gardeners using floating row covers to exclude egg-laying females, removing and destroying infested leaves and preserving natural enemies (parasitic wasps) which help control leafminer populations. See links for additional management options for home and commercial use.

2021 Billbug Grub Control

General Landscape and Garden    Treasure Valley

Billbug Grub

Posted on: May 12, 2021 by Nic Usabel

The term grub is used to designate the larvae of lawn damaging insects. In Idaho, the most common and destructive is the billbug. There are four species of billbug in Idaho: Bluegrass, Rocky Mountain, Phoenix, and Hunting.

Current degree day modeling indicates that 30% of adult billbugs are present with a forecasted 50% adult billbug activity on May 26. If you commonly experience billbug damage, your neighborhood experiences billbug damage, or you have Kentucky Bluegrass this timeframe can be used to apply a systemic insecticide for controlling billbugs if you desire.

Nonchemical control methods include selecting turf varieties of tall fescue, fine fescue, and perennial ryegrass. Select endophytic cultivar(s) in which a fungus produces a compound toxic to grubs.

Systemic insecticide control is most effective. Choose a product that lists one of the following active ingredients: chlorantraniliprole, clothianidan, imidacloprid, or thiamethoxam. Follow label instructions to ensure safety and success.

2021 Apple Codling Moth, First Generation

General Landscape and Garden    Treasure Valley

Codling Moth Cydia pomonella

Posted on: May 12, 2021 by Nic Usabel

The first apple codling moths were trapped at the end of April (Biofix on April 26). Currently the degree day model is reporting 138 degree days (DD) as of May 11. There are different management options to consider when controlling this pest.

Option A: Starting at 200 DD, forecasted to be May 15, apply a mixture of water and horticultural oil at 1% concentration to smother egg infestation. Follow with first application of insecticide at 350 DD. Reapply insecticides based on the protection interval stated on the label.

Option B: Starting at 220-250 DD, forecasted to be May 17, apply insecticides that target newly hatched larvae. Reapply insecticides based on the protection interval stated on the label.

Reference publication links to view insecticide options for commercial or residential sites. Commercial products with the active ingredients including; spinetoram, acetamiprid, chlorantraniliprole, etc. Residential products with active ingredients including; lambda-cyhalothrin (restricted use pesticide), or esfenvalerate and Spinosad (general-use pesticides).

Cultural control options include bagging the fruit once the fruit is ½ to ¾ inches in diameter. An insecticide application may be required before bags are applied to prevent early infestation. For a home /small orchard remove and dispose of young, damaged fruit by checking regularly. Placement of corrugated bands of carboard around the lower trunk can attract larvae looking for a place to pupate. Place bands in May and remove before adults begin to emerge in June.

This pest needs prevention all season long for clean fruit.

2021 Lilac-Ash Borer

General Landscape and Garden    Treasure Valley

Lilac-Ash Borer Podosesia syringae

Posted on: April 30, 2021 by Nic Usabel

The lilac-ash borer (Podosesia syringae), a clear-wing moth, can be a destructive pest for many species of ash (Fraxinus spp.), previt (Ligustrum spp.), lilac (Sryinga spp.).

The Lilac-ash borers have been caught in traps. Adults are short-lived and typically deposit all eggs within a week after emergence. The first spray should be applied 10-20 days after adult emergence, approximately May 10, before the larvae bore into the trunk. Spray should be applied to the trunk and larger limbs, follow label instructions for application and reapplication depending insecticide selected.

Primary insecticides include permethrin (group 3A), bifenthrin (group 3A) and endosulfan (restricted use; group 2A). Please note that imidacloprid (group 4A), a systemic insecticide, is ineffective against lilac-ash borer and should not be used.

Diversifying species in the landscape, maintaining optimum plant health, monitoring, and preventive sprays (if necessary) are the best methods for preventing infestations. Only preventative treatments exist.

2021 Idaho Master Gardener Plant Diagnostic Clinics & Plant Sales

General Landscape and Garden    Treasure Valley

Posted on: April 17, 2021 by Nic Usabel

Plant Diagnostic Clinic:

Many University of Idaho Extension offices offer a free plant
diagnostic clinic where certified Idaho Master Gardener volunteers help answer
clientele questions. Here are the details that were shared with the PNW Pest Alert
Network.

Don’t see your county listed? Use the first link below to
find all county locations in Idaho.

Spring Garden Plant Sale:

  • UI Extension, Ada County (Boise, ID): Let’s get growing! The
    University of Idaho Annual Master Gardener Plant Sale will be held Saturday,
    May 1st from 9:00 a.m. to 12:00 p.m., at the Ada County Extension Office, 5880
    Glenwood Street, Boise. Offerings include houseplants, herbs, vegetables, and
    berries, flowering perennials, gardening books, and so much more. Cash or check
    only. Please no early birds. For more information, call the Master Gardeners at
    (208) 287-5900. Come join the fun!
  • UI Extension, Canyon County (Caldwell, ID): Searching for
    new plants to add to your garden or landscape? The University of Idaho Canyon
    County Master Gardener Spring Garden Plant Sale will be held on Saturday, April
    24th from 9:00 AM to 1:00 PM, at Canyon County Extension Office, 501 Main
    Street, Caldwell. New this year will be the virtual pre-sale opening Monday,
    April 19 and closing Friday, April 23. Items can be pre-ordered at https://bit.ly/ccmgstore and are available
    for pick up Saturday, April 24 from 9:30 AM to 11:30 AM. Available plants
    include vegetables, herbs, houseplants, succulents, flowering perennials,
    native plants, and so much more. Join in the fun! For More information, call UI
    Extension, Canyon County at (208) 459-6003.


2021 Rose & Grapevine Pruning

General Landscape and Garden    Treasure Valley

Posted on: April 2, 2021 by Nic Usabel

It’s time to prune roses and grapevines in the Treasure Valley. The cold temperatures are milder, and the forsythia is in full bloom.

ROSES:
For a guide to pruning roses click the first link below. For a video tutorial click the second link below.

GRAPEVINES:
The University of Idaho Research & Extension Center in Parma recommends pruning grapevines in the Treasure Valley no sooner than mid-March to ensure that low temperatures do not kill buds after pruning. Grapevines can “bleed”, movement of sap from the cut, heavily when pruned in spring. This does not harm the vines. For a pruning guide on grapevines click the third link below. For a video tutorial click the fourth link below.

Additional sources not provided in the links below include Grapevine Management from Utah State University at https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=2672&context=extension_curall and Pruning Roses from Colorado State University at https://planttalk.colostate.edu/topics/trees-shrubs-vines/1763-pruning-roses/.

For additional questions on rose or grapevine pruning reach out to a local University of Idaho Extension office. Find your county office by visiting https://www.extension.uidaho.edu/find.aspx.

2021 Hard Frost Forecasted

General Landscape and Garden    Treasure Valley

Posted on: March 29, 2021 by Ruth Givens

Hard frost is forecasted for Monday 3/29 and Tuesday 3/30 nights. If fruit trees are blooming cover to protect fruit. Uncover during the day. For more details see the link below.

2021 Mosquito Management Webinar

General Landscape and Garden    Treasure Valley

Posted on: March 29, 2021 by Nic Usabel

A free virtual webinar titled "Mosquito Management: An Integrated Approach" will be hosted by University of Idaho Extension, Canyon County on Tuesday, April 13 2021 at 6 PM MDT.

In this webinar James Lunders, District Director for Canyon County Mosquito Abatement District, will discuss control of larval and adult mosquitos, surveillance of mosquito borne diseases, and how to protect yourself, pets, and livestock.

Registration should be completed at https://bit.ly/2Cmosquito

To see the flyer visit http://bit.ly/2QosdEE

2021 Spring Lawn Fertilization & Care

General Landscape and Garden    Treasure Valley

Posted on: March 15, 2021 by Nic Usabel

Spring lawn fertilization for cool season grasses recommend that fertilization be made while energy is being directed to root growth, which follows with leaf growth. This timeframe for cool season turf in the Treasure Valley traditionally March thru early May. If mulching is a practice in your lawn maintenance plan, nitrogen can be reduced by ½ pound annually. Attend a “Lawn Care for Success” class to learn more about maintenance, fertilization, and watering. Click the link https://bit.ly/21Lawn2C to register for the class.

The proper rate of fertilizer application is best achieved when using a soil test result to identify the fertilizer needs of the soil. Use the second link below to access a publication to help calculate rate of fertilizer application for the lawn. Applications should be split between spring and fall. Application rates should not exceed 1 pound of nitrogen per 1,000 square feet in any one application, access the third link below to review the publication to identify additional time(s) for application if rate would exceed the 1 pound of nitrogen per 1,000 square feet limit with only and spring and fall application. Always follow label directions.

For more information on how to obtain a soil sample to a soil test submission contact your local University of Idaho Extension office. Contact information can be found at https://www.extension.uidaho.edu/find.aspx

Another method of identifying application rate is based on the level of turf maintenance from low to high traffic. Application rates should not exceed 1 pound of nitrogen per 1,000 square feet in any fertilizer application and always follow label directions. Review descriptions, timing, and rate of application below.

1. Light use is classified as occasional foot traffic or little to no play from children. Annual turfgrass recommendation is 0-1 pound of nitrogen per 1,000 square feet. Split the application between a spring and fall application.

2. Moderate Use: Typical children’s play and occasional garden parties. Annual turfgrass recommendation is 2-3 pounds of nitrogen per 1,000 square feet. Split the application equally between a spring, early fall (late September) and late fall (Mid October to Late November)

3. Heavy Use: Frequently used sports field play, heavy traffic and/or frequent garden parties. Annual turfgrass recommendation is 4-6 pounds of nitrogen per 1,000 square feet. Apply 1 pound of nitrogen per 1,000 square feet in spring, 0.5 pound of nitrogen per 1,000 square feet late May/early June, 0.5 pound of nitrogen per 1,000 square feet late June/early July, 1 pound of nitrogen per 1,000 square feet early fall (late September) and 1 pound of nitrogen per 1,000 square feet late fall (Mid October to Late November).

If your lawn is suffering from soil compaction or development of a thick thatch layer core aeration can be completed in the spring but is preferred in fall while weed pressure will be reduced. For more information on core aeration reference the fourth publication link below.

Spring provides the opportunity to seed new turfgrass areas or to over-seed areas that may have been damaged over the winter. Cool temperatures will promote germination and growth of cool season turf species, tall and fine fescues, perennial ryegrass, and Kentucky bluegrass. Weed pressure can be higher this time of year so consider your weed control options or consider overseeding in the fall. Select pest resistant or recommended turfgrass cultivars when possible.

If there are additional questions on lawn care or weed management reach out to a local University of Idaho Extension office.

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.

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

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.

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.

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.

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.

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.

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.

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.

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.

2020 Apple Codling Moth, Third Generation

General Landscape and Garden    Treasure Valley

Codling Moth Cydia pomonella

Posted on: August 27, 2020 by Nic Usabel

The third generation of codling moth egg hatch has begun. Current degree day models indicate 2168 DD as of August 26. Third generation egg hatch begins at 2160-2200 DD.

Continue to keep fruit protected through approximately September 15. Protection of fruit can stop after that time, even if fruit has not been harvested. By mid-September there is not enough day length to signal n eggs in the fruit to hatch.

Follow label directions for harvest or post-harvest requirements.

2020 Blossom-End Rot

General Landscape and Garden    Treasure Valley - Idaho

Blossom-end rot

Posted on: August 19, 2020 by Nic Usabel

Blossom-end rot is showing up on tomato plants. Pepper, eggplant, squash, and watermelon can also be affected.

Blossom-end rot is a physiological disorder due to a shortage of calcium in young fruit. Blossom-end rot often occurs when soil moisture fluctuates as water stress interferes with calcium uptake in the plant. Most Treasure Valley garden soils have enough calcium and additions are not recommended. Refer to soil test results.

Cultural control practices: Use infrequent deep irrigation to keep the soil uniformly moist and avoid water stress or fluctuating soil moisture. Organic mulch can be used to prevent wide fluctuations in soil moisture. Avoid over fertilizing and hoeing or cultivating near the roots.

Pesticide Math Online Training

General Landscape and Garden    Treasure Valley - Idaho

Posted on: August 17, 2020 by Nic Usabel

The UI Extension Pesticide Safety Education Program has produced three educational online training courses available for pesticide applicators, Master Gardeners, and homeowners. The Calculate Pesticides series includes real-world pesticide calculations in the following courses:

1) General Math – review basic math concepts needed for calculating pesticides.
2) Using Sprayers – develop math skills for calibrating yourself to application equipment.
3) Application Rates – identify the math formulas necessary to calculate pesticide application rates.

Simply, create your account at the National eXtension website by using this address https://campus.extension.org/course/view.php?id=1588 (also linked below). Each user must have their own identification name and password. Once you confirm your free account, you will have unlimited access to these online educational materials. If you have any questions, please contact Kimberly Tate at ktate@uidaho.edu.

2020 Blossom Drop on Tomatoes and Peppers

General Landscape and Garden    Treasure Valley

Blossom Drop

Posted on: August 3, 2020 by Nic Usabel

Blossom drop during this time of year is generally associated with temperature changes. Pollen becomes sterile during hot weather. Blossom drop and/or lack of fruit set can also be caused by too much nitrogen and water stimulating leaf growth over fruit set.

Tomatoes will experience blossom drop when evening temperature drop below 55 degrees or daytime temperatures exceed 90 degrees for an extended period. Cherry type tomatoes can set fruit over a wider range of temperatures as compared to larger fruited types.

Pepper blossoms are found to be more sensitive to temperature fluctuations during the stage of pollination. Blossoms can fall off before pollination when temperatures fall below 58 degrees and daytime temperatures rise above 85 degrees.

Remember that deep and infrequent watering is best.

2020 Peach Twig Borer, Second Generation

General Landscape and Garden    Treasure Valley

Peach Twig Borer (Anarsia lineatella)

Posted on: July 24, 2020 by Nic Usabel

The second generation of peach twig borer will begin egg hatch today. Current degree day models indicate 1182 as of July 23. Second generation cover sprays begin at 1200 DD, currently forecasted for today. First cover sprays for second generation should be applied now.

For management control options review the PNW Handbook link below to select a control option appropriate for the operation. Apply according to label directions.

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