Invasive pests on trees and ornamentals

Invasive pests on trees and ornamentals

In the last few years, several very devastating pests have arrived that infest specific plants in various locations throughout the USA.  The list includes the ficus whitefly in Florida; the hemlock woolly adelgid in hemlocks throughout the Appalachian mountains, now spreading to surrounding areas; emerald ash borer in the great lakes states spreading out as far as Tennessee, Missouri, Maryland and by the Hudson river in New York; chili thrips in Texas and other warm climates; marmorated stink bug in the Eastern US across many Midwest states; myoporium thrips in California; and others.  There is also a royal palm bug and a red palm mite that suck juice from the fronds of palm trees.  As travel and international trade continues these invasive pests will continue to invade.  This blog writer will write about some of these pests individually as the season progresses.

These pests arrive with a susceptible host plant or plants that have no resistance to a place where there are no natural predators to keep the population under control.  Ficus, or fig, hemlock, and ash trees are being killed causing heavy financial burdens to homeowners and cities who have to pay to treat or remove these dead trees.  People like trees in their yards and trees lining the streets to keep the neighborhoods fresh, cooled, and beautiful.  Trees cool the environment and shade our homes to lower air conditioning costs.  Losing the trees can reduce the value of the home.  From my youth, I loved climbing trees and climbed as high as possible until I no longer trusted the small branches to hold my few pounds of weight.

What do homeowners do to care for trees that are infested?  Number one choice of many is nothing.  Yes, you can do nothing and with ficus white fly, hemlock woolly adelgid and emerald ash borer, your tree will most likely become infested and after three to five years will die.  Then it will either fall down in a few more years or you will have to cut it down.  Trees falling can injure people and cause damage to nearby cars, homes, and other trees and shrubs.  Cutting trees down on your terms is always better than letting nature put the tree down.  The second choice is to treat the tree to kill the invading insect and save your tree.  Research has shown that you can treat the tree yourself or have it professionally treated with similar positive results.  Get the tree treated before it has declined by 40% or more and your chance of saving the tree is very high. 

Professionals may spray the tree with a high powered spray to kill insects on the outside of the tree that suck juices from the tree -  like ficus white fly and hemlock woolly adelgid.  These types of sprays may also coat the tree trunk and leaves and leave a residual spray that will kill new insects that land on the trunk or leaves for a period of time.  The second type of professional treatment is to drill holes into the tree trunk at the base and inject insecticides into the tree.  When the insect chews or sucks juice from the tree, it gets a lethal dose of insecticide and dies. 

Homeowners rarely have the type of sprayer that allows them to spray higher than about 15 feet.  Many of the insecticides used by professionals can be purchased by homeowners and used with similar results.  These can be applied by drenching or placing granules near the trunk of the tree and watering it into the soil.  These products are very effective when insects drill into the tree and eat the cambium layer.  Research has shown these applications can be just as affective as professional applications.  The cost of these pests on a mature tree may be $1500 for tree removal, $200 for a professional treatment or $20 to $40 for do-it-yourself treating. 

What would a homeowner use?  Several companies provide products.  Imidicloprid is widely used under several product names.  Those names include several brands from Bayer Advanced with the Merit brand, Bonide, Green Light and others usually with Tree & Shrub in the brand name.  Green Light markets a unique product with dinotefuran brand named Safari.  Trade names with the Safari brand include Tree & Shrub with Safari, Emerald Ash Borer Killer and Rose & Flower with Safari Insect Control.  Both imidicloprid and dinotefuran effectively control insects.  Safari gets into the tree or shrub fast because it has higher water solubility and lasts for several months in the tree.  Imidicloprid takes longer getting into the tree, moves slower in the tree but lasts for a few months longer than Safari because it has very low water solubility. 

From a personal point, I have treated an azalea bush with Tree & Shrub with Safari that had skeletonized leaves.  Two days later a bunch of little green worms were all dead and laying on the ground under the bush.  Two red pine trees with woodpeckers attacking them for the insects were treated and both have stayed alive and are recuperating nicely.  One of the red pines had about 75% of the needles lost due to insect injury.  Another tree died before I treated the living tree and the insects had eaten the cambium layer under the bark.  These products are amazing at killing insects that attack trees and shrubs. 

If you live in an area with these insects, do treat your trees.  Doing so will save the tree and maintain the value of your property.

The Garden Doc

When to plant vegetables

March 18, 2011

My NCAA men’s tournament bracket choices are showing to be less than stellar.  The sun is shining and I am itching to plant garden vegetables. I just can’t plant through the snow that is still covering my garden spot.  When is the appropriate time to plant?  Below is my personal guide with my reasons.

Early crops

Onions, peas, radishes, and most cole crops can be planted very early.  They are very hardy and can withstand a frost.  Many of these plants have inherent tolerance to light frosts.  Potatoes will freeze but they will regenerate if frostbitten and continue to grow well.  Transplanted crops like broccoli and cabbage must be acclimatized to cold weather or they will freeze.  I planted potatoes on March 17 in OH and was eating small potatoes in mid June.  I will plant the above crops as soon as I can reasonably till the soil and get the seed in without having to plant in mud.

Mid season crops

Several vegetables grow quite well in cool weather but can’t be frozen.  These are carrots, lettuce, sweet corn, red beets, swiss chard, and sometimes tomatoes and beans.  Some crops like beans can be seeded before frost ends but they germinate very slowly in cold weather and may not emerge until the threat of frost is over.  The difference is they take 3 weeks to germinate in cold weather but can germinate and emerge in 5 days in warm weather.  Sweet corn and garden peas have growing points that stay below the soil for a long time and can regenerate the plant if it freezes.  Still, any frost isn’t really good for the plant.

Late season crops

Many people would put tomatoes with this group along with sweet potatoes, okra, all melons, cucumbers, squash, pumpkins, and beans also fall into this category.  If a seed grows by pushing the seed up and the two parts of the seed become the two first leaves, it is probably a late season crop.  The growing point is above the soil line and may freeze easily. 

Most seeds, if planted very late in the fal,l would germinate and grow based on when the soil temperature is right.  The soil temperature corresponds to the season and often will allow the crop to either avoid frosts or the crop will be able to tolerate a light frost.  Vegetables that can’t tolerate frost will germinate late enough that they usually don’t emerge until after the threat of frost is over. 

Early crops grow rapidly in cool temperatures and continue to grow well in warm weather.  Late season crops stagnate in cool temperatures and grow very rapidly in warm weather.  In fact, corn in hot humid weather can grow so fast you can hear squeaking as the expanding leaves slide by the other leaves coming out of the whorl.

My plans are well laid in my head, may yours be also.

Crabgrass Control and Prevention

Sorry for missing last week, personal issues interferred.

Crabgrass Control and prevention

The second most problematic weed behind dandelions in lawns is crabgrass.  As with most problems, prevention is better than curing.  If your lawn is mostly free of crabgrass, never, never let crabgrass go to seed.  Weed seeds can last for many years in the soil.  Problems in lawns but not ornamental beds, or ornamental beds but not lawns will be a problem in both if either is left uncontrolled.

Preventing crabgrass is as simple as buying and correctly applying crabgrass preventers to your lawn and ornamental beds.  Some of the many products that may be used are (listed in order of choice by the The Garden Doc):

(I apologize to companies whose products are not listed, I intentional did not list many store brands)

Products with Dimension (dithiopyr) Can be used in lawns and ornamental beds. 

• Crabgrass Preventer with Dimension is a great product from Green Light.
• Vigoro Weed Stop Crabgrass & Weed Preventer (Dimension)
• Ace Green Turf Crabgrass Preventer & Lawn Fertilizer (Dimension) (36-3-4)
• Sta-Green Crab Ex (Dimension) 

Products with Barricade (prodiamine)

• Penningtons Crabgrass Preventer, a fertilizer with Barricade.
• Ferti-lome All Season’s Crabgrass & Weed Preventer (Barricade) (16-0-8)

Combination products

• Amaze from Green Light is a combination of Surflan (oryzalin) and Balan (benefin).  It can only be used in warm season grasses, Bermudagrass, St. Augustine grass, fescue, centipede, zoysia, and bahaigrass.  It is also excellent in all ornamental beds.
• Ferti-lome Crabgrass Preventer (Team) (20-0-3) Products with Team, a combination of Balan and Treflan (Chemical name is trifluralin)

Products with Pendelum (pendimethalin)  Can be used in lawns

• Scott’s Crabgrass Preventer - (Pendelum) (32-3-8)
• Scott’s Halts

Products with quinclorac are used for post emergence control but quinclorac does have about 45 days of residual control.  This is not sufficient for good crabgrass control.

There is one chemical, Tupersan, (siduron) that can be used when seeding new grass. 

• Preen New Lawn Crabgrass Control (Tupersan) (11-23-10)

The following describes each chemical with pros and cons (again in the order of choice by The Garden Doc).  Descriptions mostly provided by Missouri Botanical Garden

Dimension® (dithiopyr) provides superior pre-emergent control of crabgrass and many other grassy and broadleaf weeds in turf grass and other ornamental plantings. It can be applied several weeks later than other products and still give effective control. It is less of a root inhibitor that some other products so damage to new seedlings is minimal.
Barricade® (prodiamine) is one of the longest-lived of the chemicals listed and is sometimes even applied in the fall for pre-emergent control of crabgrass and many other grassy and broad leaved weeds. Since it has a long residual, grass seedling failure from this product is a common pitfall.
Amaze contains oryzalin which has the longest soil residual of these products.  Balan gives excellent control of early crabgrass and oryzalin gives very long residual control.  However, Amaze can only be used in warm season grasses.
Team® is a product that gives good early control with the Balan and longer acting control with the Treflan. Team is a traditional combination of a 2:1 ratio of Balan to Treflan. This product has a distinctive orange/yellow color but is not as prone to staining as Pendelum.
Pendelum® (pendimethylin) is another commonly used, cost effective pre-emergent crabgrass control. It has similar chemistry to Team. Its granules have a characteristic yellow/orange color and may produce staining on sidewalks and driveways. It is not particularly long lived in the soil. Pendimethylin also acts as a root inhibitor so it may have negative effectives on newly emerged turf grasses.  The Garden Docs additional comment – With high rainfall Pendelum can wash out of the crabgrass germination zone.
Tupersan® (siduron) is the only crabgrass pre-emergent chemistry that will allow cool season grasses to germinate. It is pricey and products with Tupersan are often hard to locate. It has a very short residual in the soil, so it must be followed up with another application or Dimension may be used for a follow-up application as long as all of the grass seed is germinated.  (The above chemical descriptions are mostly taken from the Missouri Botanical Garden web site and posting: http://www.mobot.org/gardeninghelp/plantfinder/pestd1.asp?ID=31)

The majority of chemicals above come from the family of chemistry called dinotroanilines.  The following all have a very yellow color and are very capable of staining.  Their staining ability is pendimethylin> trefluralin=oryzalin=benefin> prodiamine. I once dropped some pendimethylin on a white pickup tailgate and the stain drops were there for as long as I had the pickup.  Dithiopyr does not stain and is a different class of chemicals.  All products need to be activated by applying about 1/4 to ½ inch of irrigation or get lucky and have a good rain within 2 weeks of application. 

The length of time each will control crabgrass is oryzalin>prodiamine>dimension>trifluralin>pendimethylin>benefin. 

Crabgrass germinates when the soil reaches 50 degrees or warmer for 5 days at the ¼-inch level. This may occur in February in the south and early May in the northern states.  A rule of thumb is crabgrass germinates when the forsythia bloom.

Dimension, Barricade and Amaze give season-long control of crabgrass from a single application.  You need to select a rate that fits the season in your area.

Do I apply a crabgrass preventer with a fertilizer?  Answer is your choice.  Often the fertilizer used as the carrier may not be the fertilizer you should choose for your lawns needs.  Or you may make the crabgrass application at the wrong time for fertilizer in your area.

Whatever choices you make for crabgrass control, remember to always read and follow the label directions.  Many lawn care givers do nothing other than mow the crabgrass which will spread seed and insure a good crop of crabgrass next year and for several years to come.

Discussion on postemergence crabgrass control will come in late spring.