Spraying dormant oil now controls bugs for coming year

Maybe gardeners aren’t busy in Minnesota or Iowa during the winter, but for gardeners living in the Mojave Desert, it is probably our busiest time of year. I’m asked about spraying dormant oils on trees, but most people don’t know anything about them. It’s a shame because it’s probably the most important method to control bugs that may become problems during the coming year. It’s good insurance.

There isn’t much time remaining to get an application of dormant oil on landscape plants and fruit trees. This one application, applied early in the season, is probably the single most important method to control bad bugs hiding in your trees and shrubs and ready to spread their numbers in 2019. And it’s very safe.

This spray, however, does nothing to control borers or that ugly leaf-footed plant bug which flies from yard to yard and appears in early summer. But it does help control what we call “soft-bodied insects” such as aphids, mites, scale insects and others that live out the winter on trees and shrubs, patiently waiting for spring growth to appear.

Don’t confuse these oils with things like Neem oil or Cinnamon oil or any of the many oils out there that are currently popular. Dormant oils are made from mineral oil or paraffin.

They have been around for decades and are not very expensive to buy and apply if you do the job yourself. If you hire a landscape professional to apply it, they must understand how this oil works and how to apply it correctly. Application methods are explained on the label.

It works best when applied on warm days without wind. Never apply dormant oil to plants that are flowering. These sprays will harm honeybees visiting the flowers and may damage the flowers as well. If there are flowers present and open, delay the spray until the flowers are gone.

Apply the oil to the entire tree or shrub, top to bottom. Give an extra shot of dormant oil at the base of the plant where these types of insects often wait out the winter. It works by suffocation. These oils are not poisonous to pets or yourself, but they are deadly to all insects that are sprayed.

I know it doesn’t feel like spring, but it’s right around the corner. Now is the time to get fertilizers applied to trees, shrubs, fruit trees and anything else that will start to grow in a week. You want fertilizers available to plants when they are ready to grow. For most plants, this is around the first week of February.

Q: With the leaves off, I got a good look at our apricot tree and found two limbs with bark severely damaged. It looks like the bark is completely gone down to the wood underneath. What, if anything, can be done to salvage these limbs?

A: Bark easily lifted from tree limbs or the trunk no longer protect anything that’s alive. Plant parts below this bark is dead, whether killed by borers or intense sunlight. Dead is dead. Unlike how animals heal, the living wood surrounding this dead area must roll back on top this dead area and cover it.

If the damaged area is more than half of the way around the limb, then consider removing it. If the damaged area is half or less, remove the loose bark and encourage it to heal properly through irrigation and fertilizers.

Removing loose bark covering this dead wood helps the plant heal faster and new growth to roll over it. Healing is a waiting game. Healing is faster if the tree is getting adequate amounts of fertilizer and water. You won’t get it to heal faster by giving it excessive amounts of water and fertilizer.

Take a sharp, sanitized knife and remove all loose bark down to fresh wood. Remove all the loose bark and slightly cut into the living wood surrounding this dead area. You will not harm the tree by cutting into the living wood if the knife is sanitized; the tree will heal faster.

Sanitizing the knife, just like the surgeon’s scalpel, will keep serious disease problems from entering the tree that might slow down the healing or worsen the health of the tree. The tree will heal quickly if it is healthy. But this knife must be sanitized with alcohol or a good household sanitizer before cutting away at it.

It is possible that apricot, unlike many peach and nectarine, will sucker or show new growth below this damaged area. If the limb must be removed, select a sucker growing in a good direction to fill the vacancy left by removing the limb. If the limb remains, remove the suckers and let the wound heal.

Q: We found borers in a large sumac as well as a Chinese pistache ornamental tree. My ash and oak tree have aphids. I want to spray dormant oil but do not have enough information about it. Do I spray only trees without leaves or can I spray evergreen trees such as holly oak and African sumac?

A: Read the label to make sure your trees are included but there should be no problem spraying trees that have leaves. It just requires applying more liquid spray because there is more surface area to spray. It’s important to spray the undersides of the leaves because that’s where most of the bugs will be hiding.

Q: My tree has a trunk that has split badly on the side facing the sun. This split is very deep and 6 feet long. Can I wrap the trunk in burlap to keep the intense sunlight off of it while it’s healing?

A: The split is in dead wood all the way through to the center of the tree. All of this wood is dead probably because of sunburn. Sunburn is a big problem with trees that have thin bark protecting them such as ash, locust, ornamental plum and even some of the desert trees.

The tree will heal this area over time if the tree is healthy and growing vigorously. The question is more about your patience and if you can wait or not. This healing might take up to four or five years depending on how the extent of damage. Trees that are vigorous growers heal most rapidly.

The damage is most likely finished, and it will probably not spread any further than this. The outside edges, just beyond the damage, will roll over and enclose this damaged area over time. How much time? It depends on how vigorous the species is and the tree’s health.

Water this tree regularly but not daily. Always skip at least one or more days when watering. Soak the soil around the tree under the canopy deeply and then wait until it needs it again.

Fertilize this tree in early spring with a fertilizer container of nitrogen. This means a big first number on the fertilizer bag. Many lawn-type fertilizers will work. You could fertilize the tree a second time in April with half of the amount of a single application, but I don’t think it’s necessary.

When new tree growth rolls over this damaged area, this new growth will be more tolerant of intense sunlight. This is because it grew there under desert conditions. No need for paint. No need for burlap trunk wrap. In fact, I worry that a covering of brown burlap might trap more heat than just leaving it exposed to the open air.

If it’s possible to cast some shade on that damaged area while it’s healing, the tree will appreciate it. But unless there are some unusual circumstances, such as a location with lots of reflected sunlight from windows or similar, it shouldn’t be necessary.

I also worry a little bit about borers infesting the area near this damage. In a few months or couple of years, these bugs may create more problems for the tree. Consider applying borer control pesticides as a soil drench around the tree after it flowers. This might help while it is recovering and keep it free of borers.

Bob Morris is a horticulture expert and professor emeritus of the University of Nevada, Las Vegas. Visit his blog at xtremehorticulture.blogspot.com. Send questions to Extremehort@aol.com.

Local Videos
Butterflies At The Springs Preserve
The butterfly habitat is now open at the Springs Preserve. Learn about butterflies and take in the peaceful surroundings. (Mat Luschek / Review-Journal)
The Bellagio Conservatory's spring display has a Japanese theme
The Bellagio's conservatory is hosting around 65,000 flowers, to form a Japanese theme this spring. (Mat Luschek / Review-Journal)
Bonnie Springs closes (Caroline Brehman/Kimber Laux)
Bonnie Springs Ranch near Las Vegas officially closed its gates Sunday, March 17, 2019. (Las Vegas Review-Journal)
Honoring a fallen North Las Vegas Police officer at his namesake school
The 20th Annual Raul P. Elizondo Honor Day celebrates the fallen North Las Vegas Police officer's legacy at his namesake school. (K.M. Cannon/Las Vegas Review-Journal) @KMCannonPhoto
Windy day in Las Vegas Valley
The Review-Journal's camera on the under-construction Las Vegas Stadium the was buffered by high winds on Wednesday, March 14, 2019. (Las Vegas Review-Journal)
March gloom falls on Las Vegas
After a rainy overnight, gloomy skies hover over Las Vegas Tuesday morning. (Mat Luschek/Review-Journal)
John Katsilometes gets his head shaved at St. Baldrick's
Las Vegas Review-Journal man-about-town columnist John Katsilometes gets his head shaved by former Las Vegas Mayor Oscar Goodman during St. Baldrick's Foundation shave-a-thon on the Brooklyn Bridge at New York-New York in Las Vegas Friday, March 8, 2019. (K.M. Cannon/Las Vegas Review-Journal) @KMCannonPhoto
The Blue Angels take flight over Las Vegas Strip
The Blue Angels’ U.S. Navy Flight Demonstration Squadron flew their signature Delta formation over a part of the Las Vegas Strip, McCarran International Airport and east Las Vegas and were scheduled to fly over Hoover Dam. (Michael Quine/Las Vegas Review-Journal) @Vegas88s
Gross World Records
A group of about 20 children gathered around a TV at Sahara West Library on Feb. 27 for a history lesson on the most disgusting world records.
Graduation for Renewing HOPE program
The Renewing HOPE program graduation for homeless who spend nine months in Catholic Charities program. Graduates are preparing to enter the workforce. (Bizuayehu Tesfaye/Las Vegas Review-Journal) @bizutesfaye
Car crashes into Starbucks near Las Vegas Strip
Lt. William Matchko of the Las Vegas Metropolitan Police gives details about a car crashing into a Starbucks at Sahara Avenue and Paradise Road, near the Las Vegas Strip, on Friday, March 1, 2019. (Jessica Terrones/Las Vegas Review-Journal)
Car crashed into PT’s Gold
A 60-year-old man who police believe was impaired drove into a PT’s Gold at Silverado Ranch and Decatur boulevards Thursday night, Metropolitan Police Department Lt. William Matchko said. The driver was hospitalized and is expected to survive. A man inside the bar was hit by debris but drove himself to the hospital, Matchko said. (Katelyn Newberg/ Las Vegas Review-Journal)
Driver crashes vehicle into PT’s tavern in south Las Vegas (part 1)
A driver suspected of impairment crashed a vehicle into the wall of a PT’s Gold tavern, at 4880 W. Silverado Ranch Blvd., in Las Vegas on Thursday, Feb. 28, 2019. (Katelyn Newberg/Las Vegas Review-Journal)
Driver crashes vehicle into PT’s tavern in south Las Vegas (pullout)
A driver suspected of impairment crashed a vehicle into the wall of a PT’s Gold tavern, at 4880 W. Silverado Ranch Blvd., in Las Vegas on Thursday, Feb. 28, 2019. (Katelyn Newberg/Las Vegas Review-Journal)
Kids Read Books To Dogs At The Animal Foundation In Las Vegas
Kids from local Las Vegas elementary schools took part, Thursday, in a program at the Animal Foundation, where they read books to dogs. (Mat Luschek/Review-Journal)
Pioneer Trail highlights historic locations in West Las Vegas
The Pioneer Trail, a 16-site route of historically significant locations in Las Vegas, starts at the Springs Preserve and snakes east until it reaches above the brim of downtown. (Bizuayehu Tesfaye/Las Vegas Review-Journal) @bizutefsya
Vegas Warm Weather Hits Las Vegas Valley
Between Feb. 20-21, parts of the Las Vegas Valley were hit with 7.5" of snow. Less than a week later, it was sunny with temperatures in the 70s. (Mat Luschek/Las Vegas Review-Journal)
Dr. S. Jay Hazan, a World War II veteran, talks about his arrest at the VA Hospital
Dr. S. Jay Hazan, a World War II Army veteran, was arrested in November after he caused a ruckus at the VA Hospital in North Las Vegas and stole his driver's car keys. He was arraigned on Tuesday, Feb. 26, 2019, and the charges will be dropped after 60 days. (Bizuayehu Tesfaye/ Las Vegas Review-Journal) @bizutesfaye
Claytee White talks about Black History Month
An interview with Claytee White, director of the Oral History Research Center at UNLV. (Benjamin Hager/Las Vegas Review-Journal)
Reflecting on the Moulin Rouge and a segregated Vegas
Former employees of the Moulin Rouge, the first integrated hotel-casino in Nevada, talk about what it was like in the brief six months the casino was open. (Rachel Aston/Las Vegas Review-Journal)
Las Vegas home prices
Home prices rose in every ZIP code in the Las Vegas Valley in 2018 for the second year in a row, according to SalesTraq. Prices grew fastest in older, more centrally located areas. But prices were highest in the suburbs. The top three ZIP codes for price growth were 89119 (29.8%), 89146 (25%) and 89030 (24.6%). The top three ZIP codes for median sales prices were 89138 ($464,500), 89135 ($420,500) and 89052 ($370,000).
Wagonwheel Drive overpass reopens after ice closure
Overpass at Wagonwheel Drive reopens after ice on the onramp caused the ramp to be shut down, Feb. 22, 2019. (Michael Quine/Las Vegas Review-Journal)
Keeping warm at the city of Las Vegas’ homeless courtyard
With help from the city of Las Vegas, a Salvation Army shelter stays open during the day Thursday and Friday, offering a safe place for the homeless to find respite from freezing temperatures and snow. (Chase Stevens/Las Vegas Review-Journal)
Sloppy, Slushy Road Conditions Lead to Slow Traffic
Traffic slowed to a crawl on Jones are near Russell as conditions worsened Thursday. (Mat Luschek/Review-Journal)
Winter storm blankets west side of Las Vegas Valley
On Wednesday evening through early Thursday a winter storm dumped more than 7 1/2 inches of snow on some parts of the Las Vegas Valley. (Michael Quine/Las Vegas Review-Journal)
Las Vegas snow day for children
Las Vegas kids play in the snow that fell on Feb. 21, 2019. (Belinda Englman/Las Vegas Review-Journal)
Snow closes Red Rock Canyon, residents enjoy rare snowfall
The greater Las Vegas area was hit with snowfall on Thursday, Feb. 22, 2019. This video shows the areas surrounding Red Rock Canyon and the Summerlin community. Video by: Heidi Fang/Las Vegas Review-Journal
Las Vegas kids attend school in the snow
Las Vegas children attend school during a rare snowstorm on Feb. 21, 2019. Staton Elementary School and other CCSD schools remained open. (Glenn Cook/Las Vegas Review-Journal)
People enjoying the snow in Summerlin
Fox Hill Park in Summerlin was busy Thursday morning, Feb. 21, 2019, with people enjoying the rare snow that fell overnight. (Mat Luschek/Las Vegas Review-Journal)
NHP advises motorists to take caution during Las Vegas snowstorm
NHP advised motorists to take caution during the snowstorm in Las Vegas. (Bizuayehu Tesfaye/Las Vegas Review-Journal) @bizutesfaye
It is a rainy Valentine's Day in Las Vegas - Video
These scenes come from the Las Vegas Stadium LiveCam (Las Vegas Review-Journal)
Life Videos
MAGIC fashion convention showcases men's clothing trends
The MAGIC fashion convention has come to Las Vegas at the Mandalay Bay Convention Center to showcase some of the hottest clothing trends for men. (Nathan Asselin/Las Vegas Review-Journal)
Former Army medic’s Afghanistan story told in new book
The graphic novel “Machete Squad” is based on journals written by Las Vegan Brent Dulak.
Las Vegas man talks about losing his wife
Dwayne Murray, 37, lost his wife, LaQuinta while she was at Centennial Hills Hospital. A jury awarded him $43 million last week after it said the hospital failed to perform the standard of care in administering a drug for her sickle cell disease.
Barber sets up shop in grandfather’s old shop
Andres Dominguez’s new barber shop is filled with memories of his grandfather, who ran the El Cortez landmark for more than 30 years. (John Przybys/Las Vegas Review-Journal)
Life and times of a 90-year-old horse player
Leo Polito of Las Vegas describes meeting legendary jockey and trainer Johnny Longden on the beach at Del Mar. Mike Brunker/Las Vegas Review-Journal.
Learning the history of singing bowls
Presentation at Summerlin Library teaches residents about the history of singing bowls (Mia Sims/Las Vegas Review-Journal)
Learning live-saving techniques in Stop the Bleed class
Leslie Shaffer, an AMR paramedic, shows how to control bleeding during a Stop the Bleed course at the Summerlin Library. The class is designed to teach anyone how to control and stop life-threatening bleeding. (Mia Sims/Las Vegas Review-Journal)
Vicki Richardson speaks about on the power of art
Artist and arts advocate Vicki Richardson talks about the power of art to inspire and challenge. (John Przybys/Las Vegas Review-Journal)
DressCoders pairs tech with haute couture
DressCoders is a startup focused on haute couture garments. The company uses illuminated thread that is washable and can be sewn right into the fabric. (Mat Luschek/Las Vegas Review-Journal)
CES 2019: Brava infrared oven
In cooking with the Brava infrared oven,there’s no preheating. the bulbs can reach 500 degrees in less than a second. (Heidi Knapp Rinella/Las Vegas Review-Journal)
Sinks Merge Style And Utility
Study could determine cause of Alzheimer’s, Parkinson’s diseases
Dr. Aaron Ritter, director of clinical trials at the Cleveland Clinic Lou Ruvo Center for Brain Health, discusses his research on how inflammation in the brain impacts Alzheimer’s and Parkinson’s diseases. (Jessie Bekker/Las Vegas Review-Journal)
Holocaust survivors talk about tragedy and friendship
Janos Strauss and Alexander Kuechel share their perspectives on life. (John Przybys/Las Vegas Review-Journal)
'Siegel Cares' Santa delivers toys to kids at Siegel Suites in Las Vegas
Siegel Cares, the charitable wing of The Siegel Group, delivered toys to families at their apartment complexes in Las Vegas. (K.M. Cannon/Las Vegas Review-Journal)
Home Front Page Footer Listing