Best to apply pest control for trees is winter

The most effective pest control measures for fruit, shade or ornamental trees during 2019 will be applied this December and January. Many gardeners consider the application of oils as an organic method of controlling future pests. In the purest sense, it is not organic. But applications of oils during the winter reduce the need for hard pesticides later.

No, this is not motor oil but a highly refined petroleum oil such as those derived from paraffin, mineral oil and even some vegetable oils used for organic production. Spray oils are combined with an emulsifying agent as a part of the container mix so it can be diluted with water when spraying.

Application rates may change with the time of year, so always consult the label. Many horticultural oils used for pest control are also used in the spring and early summer months when temperatures are cooler. Never apply it when the plant is flowering, when pollinators like honeybees are present or during hot weather.

Winter or dormant oil applications must be applied at the right time and done correctly if they are to be effective. The perfect time for first spraying is after leaf drop and when tree pruning has been completed. The perfect weather is when it’s warm, the sun is out and there is no wind at all.

When making this spray application, the weather must be warm because all insects become active during warm weather. It must not be windy or the oil sprays are pushed off course and applied unevenly. To get good control, that blanket of oil should be even and uninterrupted, covering most of the tree.

The entire tree — top to bottom, tops of the limbs and bottoms of the limbs — is sprayed. This spray covers the tree in a blanket of thin oil, suffocating future insect problems that are riding out the bad winter weather on the trunk and tree limbs. They are waiting for spring. If not interrupted, they launch a new surge of spring and summer feeding and egg laying and gardening problems.

These oils come under a variety of names, including dormant oil, spray oil, horticultural oil, dormant spray and others. It’s not the same as neem oil, which is a true natural insecticide.

Most ugly, overgrown shrubs can be cut nearly to the ground, and they will grow back. Some grow back faster than others, but if the shrubs are truly ugly in their present condition, it might be worth cutting them back and letting them regrow into a new, young looking shrub.

This is a legitimate pruning technique called rejuvenation pruning. An application of a tree and shrub fertilizer in February or March will cause these pruned shrubs to grow back faster.

If you aren’t sure whether pruning will work, look at the base of the plant. Do you see any small suckers at the base? The suckers are a good indicator the plant will grow back easily if cut way back.

Fertilizing a winter lawn now prevents it from turning brown due to cold damage this winter. If you are not sure how much to apply, take the first number on the fertilizer bag and divide it into 100. The resulting number tells you how many pounds of fertilizer to apply for each 1,000 square feet of lawn area. By the way, now is an excellent time to apply weed killers to lawns to control difficult, perennial weeds.

Wait until the last week of February or first week of March to prune grapes. Grapes get damaged during the winter months in the Mojave Desert, even when they’re watered properly. It’s best to wait for that time period of yucky weather to pass before pruning. Roses, on the other hand, are typically pruned here in January.

There is no reason to apply fertilizers during the winter months unless your plants are actively growing, such as some of the winter vegetables and annual flowers. Fertilize winter vegetables and annual flowers lightly about once a month. Apply granular fertilizer about 4 inches in parallel with the row of vegetables. Yes, fertilize vegetables during the winter months.

Don’t prune palm trees during the fall and winter months. This is the absolute worst time for planting or pruning these trees. Plant them during the spring or summer months. Prune them in the spring when their flowers are present but before they form seed. At this time both fronds and flowers can be removed so seeds are not a problem.

Q. What is the best fruit tree for containers?

A. That is a loaded question because there are many types of fruit trees that grow here. Plant a fruit tree that stays small. Some citrus like kumquats and most lemons and limes stay small. Genetic dwarf or miniature fruit trees are a good choice. If it’s a tree sensitive to winter freezing temperatures, use a lightweight soil mix so the container can be moved.

• Light. All fruit trees need at least six hours of unfiltered sunlight every day. That’s a minimum. They perform better with more. If it is filtered or reflected light, then they need more hours.

• Wind. Many fruit trees, like some citrus and plums, cannot handle windy locations. Windy locations in a yard usually include narrow passages between buildings. These locations channel wind and increase its speed once it enters these narrower areas.

• Soil. Fill the container, leaving at least 2 inches unfilled at the top. Purchase a soil moisture meter for house plants and use this to judge how often to water. Push the probe end of the meter about 4 inches into the soil to measure moisture near the roots. Don’t let the meter register below six before irrigating again. In hot locations and smaller containers, apply water twice per day during the hot summer months.

• Watering. Apply enough water so that one-fourth of it drains out the bottom. The container should have drainage holes in the bottom.

• Double pots. If the container is in direct sunlight, place the container with the plant inside a larger container. The outside pot shades the outside walls of the inside container so that the soil and plant roots remain cooler.

• Fertilizer. Mineral fertilizers or a very nutrient-rich compost can be used. Apply mineral fertilizers twice a year — once in early spring and again after harvest. When using mineral fertilizers, the soil will eventually “run out” of soil organics. Repotting or replanting the tree is the best way to get organics back in the soil again.

Compost can be used as a substitution for mineral fertilizer if the compost is rich in nutrients. It should be applied only once a year in the spring.

• Replanting. Plants with roots growing in containers have a restricted area of soil where plant nutrients are available. This means that nutrients inside containers are exhausted after a few years. Replenish this soil with compost every three to five years.

Q. What is the best way of removing scale insects from a bay laurel tree?

A. Scale insects are difficult to control because they live under a hard, outer scale that covers their bodies. From under this outer protection, they suck plant juices, and insecticides seldom give much control.

Repeated oil sprays are probably the best method. Buy a spray oil that can be applied during the winter, late spring and early summer months. It may be called a summer oil, but these oils come under a variety of different names.

This oil can be mixed with water because it contains an emulsifier. The water and oil combination is sprayed on the tree limbs where the scale insects are located. This oil application suffocates the scale insect when it appears in the early spring, spring and early summer months.

Oil applications will also control the aphids. Ants like both aphids and scale insects and will spread them around on the trees, so get ants under control as well.

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

The Mob Museum
Saddle bronc rider Joey Sonnier earns spot at NFR after overcoming years of drug addiction
Joey Sonnier started saddle bronc riding at 18, but at 20 he began using methamphetamine to cope with the work of the rodeos and became addicted. At 39, after years of addiction and a low point that pushed him to rehab, he's qualified for the National Finals Rodeo. (Rachel Aston/Las Vegas Review-Journal)
Core Arena opens at the Plaza downtown in time for NFR
Core Arena, downtown's first permanent outdoor equestrian center, opens to the public at the Plaza. The arena will be used for events throughout the year, including the 10-day 2018 Wrangler National Finals Rodeo at the Thomas
MountainView Hospital celebrates the opening of the new Sunrise Health GME Simulation Center.
MountainView Hospital celebrates the opening of the new Sunrise Health GME Simulation Center. (Bizuayehu Tesfaye/Las Vegas Review-Journal) @bizutesfaye
NFR Preps Livestock for the Limelight
NFR’s Jed Pugsley discusses the care that goes into preparing the rodeo’s livestock for Las Vegas’ big event.
Grand Menorah lighting begins Hanukkah
Rabbi Shea Harlig led the ceremonial lighting of the menorah to begin Hanukkah at the Fremont Street Experience. There were also performances by the Desert Torah Academy's choir and the Dancing Dreidels. (Rachel Aston/Las Vegas Review-Journal)
Perla Gumm has spent the past few years collecting toys for kids for the LV Rescue Mission
Perla Gumm has spent the past few years collecting toys for kids for the LV Rescue Mission. It's something she started even before the rescue mission was her beneficiary; she just felt a need to collect toys and teamed up with them later. Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye
Marvin Menzies on Cincinnati
UNLV basketball coach Marvin Menzies talks about Cincinnati and his own program. Video by Mark Anderson/Las Vegas Review-Journal
Tony Sanchez wraps up the UNLV season
UNLV football coach Tony Sanchez wraps up the season. Video by Mark Anderson/Las Vegas Review-Journal
Tony Sanchez wraps up the UNLV season
UNLV football coach Tony Sanchez wraps up the season. Video by Mark Anderson/Las Vegas Review-Journal
Joey Logano talks about Champions Week in Las Vegas
NASCAR champion Joey Logano talks about the future of Champion's Week in Las Vegas, Nevada, on Nov. 28, 2018. (Ron Kantowski/Las Vegas Review-Journal)
Rain hits Las Vegas Valley
Widespread rain hit the Las Vegas Valley on Thursday, Nov. 29, 2018. (Rachel Aston/Las Vegas Review-Journal)
Las Vegas Valley Hit with Rain, Clouds
Rain and clouds hit the Las Vegas Valley on Thursday afternoon.
Ducks have Lorenzi Park to themselves
Thursday’s rain kept people inside, leaving Lorenzi Park to the ducks.
Kyle Busch Reflects On Disappointing End To Nascar Season
Kyle Busch reflects on disappointing end to his 2018 season during NASCAR Champion's Week in Las Vegas, Nevada, on November 28, 2018. (Ron Kantowski/Las Vegas Review-Journal)
The Animal Foundation's Lost & Found offers community options for lost pets
The Lost & Found at The Animal Foundation allows members of the community to turn in lost pets or retrieve them. They recently started using the Finding Rover app that uses facial recognition to find and report lost pets.
The National Atomic Testing Museum is a Blast
Brookman Elementary School sets world record
All 776 students at Brookman Elementary School helped set a world record by connecting a chain of pipe cleaners that measured more than 11 miles. Student got 10 pipe cleaners for every book they read. (K.M. Cannon/Las Vegas Review-Journal)
UNLV’s football players painted the Fremont Cannon red in celebration to their victory against Reno.
UNLV’s football players painted the Fremont Cannon red outside of the Student Union in celebration to their victory against in-state rival the University of Reno. Bizuayehu Tesfaye/Las Vegas Review-Journal @bizutesfaye
Barn Buddies Rescue
Barn Buddies Rescue is a non-profit dedicated to the rescue of abused, neglected or abandoned farm animals.
R-J's Mark Anderson on UNLV's victory
Review-Journal sports reporter Mark Anderson recaps UNLV's victory over Southern Utah. Video by Mark Anderson/Las Vegas Review-Journal
Marvin Menzies on beating Southern Utah
UNLV basketball coach Marvin Menzies talks about the victory over Southern Utah. Video by Mark Anderson/Las Vegas Review-Journal
Michigan State talks Las Vegas Invitational win
The Spartans defeated Texas 78-68 at Orleans Arena on Friday.
Three Square’s Maurice Johnson Talks About Food Waste
Three Square’s director of operations Maurice Johnson talks about food waste. (Ben Hager/Las Vegas Review-Journal)
Armani Rogers on his return to playing
UNLV quarterback Armani Rogers talks about being back on the field. Video by Mark Anderson/Las Vegas Review-Journal
Black Friday at Fry's
Shoppers line up for deals early on Black Friday at Fry's Electronics on Las Vegas Boulevard South. (Mat Luschek/Las Vegas Review-Journal)
Menzies on state of UNLV's team
UNLV basketball coach Marvin Menzies talks about where his team stands after four games. Video by Mark Anderson/Las Vegas Review-Journal
Tony Sanchez on possibly changing the UNR date
UNLV football coach Tony Sanchez talks about the idea of changing the UNR date to Nevada Day. Video by Mark Anderson/Las Vegas Review-Journal
Women’s shelter gets $1.5 million dollar renovation
The Shade Tree, which offers food, shelter, facilities and services to women, gets a $1.5 million dollar renovation.
UNLV's Drew Tejchman on playing safety
UNLV wide receiver Drew Tejchman talks about also playing safety. Video by Mark Anderson/Las Vegas Review-Journal
Hailey Dawson Day
Roy Choi on cooking for Park MGM employees
As he prepares to open his new restaurant Best Friend later this month at Park MGM, celebrity chef Roy Choi took the time to cook for the resort’s employees Tuesday. (Al Mancini/Las Vegas Review-Journal)
Best Friend Menu Reveal Wednesday
Chef Roy Choi tells us what to expect from Wednesday’s Facebook Live Menu Reveal for his new Park MGM restaurant Best Friend. (Al Mancini/Las Vegas Review-Journal)
Las Vegas Great Santa Run
People participated in the 14th annual Las Vegas Great Santa Run which raises cubs for Opportunity Village.
World Holidays Exhibit At The Natural History Museum
Migratory Bird Day teaches adults and kids to celebrate birds
Different organizations offered activities for kids and adults to learn about birds and celebrate their migration journey at Sunset Park. (Rachel Aston/Las Vegas Review-Journal)
"Jackson: The Red Rock Canyon Burro" is a children's book about Red Rock Canyon
"Jackson: The Red Rock Canyon Burro" is a children's book about Red Rock Canyon (Janna Karel Las Vegas Review-Journal)
Interfaith Amigos speak in Las Vegas
Celebrity photographer dedicates dance book to Las Vegas shooting victims
Behind the scenes with local celebrity photographer Jerry Metellus as he talks about his Dance For Vegas coffee book dedicated to the 58 victims of the October 1 shooting. (Marcus Villagran/Las Vegas Review-Journal) @marcusvillagran
Dreamsickle Kids Foundation founder Gina Glass talks awareness
Gina Glass, 35, founded Dreamsickle Kids Foundation to raise awareness for sickle cell disease in Nevada. (Jessie Bekker/Las Vegas Review-Journal)
News Headlines
Add Event
Home Front Page Footer Listing
You May Like

You May Like