Plant Answers  >  THE UNBEATABLE FOES

THE UNBEATABLE FOES

I want to publically apologize for some of my media colleagues who have been recommending natural-sounding remedies which do NOTHING to solve target problems which are seasonal and feasiblely uncontrollable. The only changes these so-called "remedies" make is a decrease in the gullible persons bank account. These atrocities became paramount to me as I listened to a garden "expert" recommend garlic extract and soil activators for multiple soil drenches to cure the cause of dead leaves on Arizona Ash trees and eliminate worms hanging from webs on the same trees. The Arizona Ash trees had dead leaves because of the fungus disease Anthracnose which occurs several times in the early spring and eventually is eliminated by hotter, drier weather. The worms come every year, complete their life cycle and disappear---as outlined and identified at: http://www.plantanswers.com/garden_column/april04/1.htm By the time the curative recommendations of garlic extract and soil activators were being made, the problems had cured themselves and only the leaf damage and the memories of the worm problem remained. Money spent on these "remedies" was completely wasted unless there were some therapeutic ramifications for the caller -- who was actually the victim of this useless, costly advice.

With that sorry episode fresh in our memories, I want to warn you of some other problems which you will need to avoid getting useless remedies for and wasting your families valuable resources on. If you have an abundance of financial resources which you wish to dispose of in a reckless fashion, I know a young man named Jeremy Parsons who would accept as much financial aid as you want to squander. Hopefully, we have the potential of getting better returns on our money invested in that project than from the use of garlic extract and soil activators! Some horticulture pitfalls to avoid:

RED TIPPED PHOTINIA PROBLEMS


Foliage disease combined with iron chlorsis problems make Red Tipped Photinias a poor shrub choice -- hollies are the answer

Red Tipped Photinias as so susceptible to iron chlorsis in some areas that the red on the leaf spots are the only red the plant displays!

It is not practical or feasible to try to prevent this foliage disease of Red Tipped Photinia

Spider Mite on Red Tip Photinia Leaf 2

This is the most commonly sold shrub and, by far, the most problem-prone shrub in Texas. This shrub is highly susceptible to Red Tip Leaf Spot and yellowing caused by iron chlorsis. There is no practical cure for either problem. There is an impractical treatment which is a product (Fertilome Liquid Systemic Fungicide) which contains Propiconazole (Alamo - Banner) of oak wilt fame. It is labeled for Red Tip Leaf Spot. Propaconazole-Banner Maxx-has been shown to be pretty good for Entomosporium leaf spot control in red tip. And here is all you have to do. Start application early and preventatively, especially while young leaves are developing and sizing up. Reapply as frequently as label will allow, probably 10-14 days, until leaves are fully mature...then re-apply as needed to protect new flushes as they occur. Plants with chronic or historical problems with leaf spot should be aggressively treated as mentioned above....plants that have not had a problem, probably scout and apply at first sign of infection, or maybe 1-2 preventative applications....also, important is to collect and destroy all infected leaf litter from below plants. Also, get a good line-of-credit from the bank before starting this treatment since every year as the plant gets larger, the treatments will be more costly. The PRACTICAL treatment is to eliminate sickly red-tipped Photinias as soon as possible and replace them with hollies. If you do not have red-tipped Photinias planted in the landscape-DON'T!!!

SPIDERMITES


Notice the green careless weed in front and purslane in the back of this heavily infested tomato plant. The weeds will be attacked later


Spidermites randomly infest plants then spread to adjoining plants as their populations increase


Notice the yellowing plants at the far right corner of this garden. Spidermites begin in pockets and spread across the entire garden spread by wind.

Spidermite infestations can occur in the top portions of the plant. Notice the damaged bush snapbeans in the immediate background.

Notice the healthy tomato foliage as compared to the light-green to yellow foliage of an infested plant

A heavily infested by spidermites plant with yellowing and drying foliage

Notice the yellowing, heavily-infested tomato plants which have started to yellow

Spidermites are the main culprit of the garden favorite, sweetpeas

Spidermites suck the green chlorophyll from foliage leaving damaged plants a lighter-green

The best cultural techniques cannot stop a spidermite invasion

The foliage of spidermite-damaged plants go from light green to yellow to dead brown. damaged

The tiny specks in the webbing around this tomato cluster are thousands of tiny spidermites

The most prolific, elusive insects (which are really spiders) of any garden are the spider mites. These girls coined the phrase strength in numbers and they are committed to the cause! When conditions are optimum (hot and dry), they can double their population in 4 days. Don't feel sorry for the requirements placed on the male in order to accomplish this feat - - their services are not required, but once. Isn't that sick?! These gals have taken woman's liberation too far; they only visit their male counterpart once during a lifetime. What's worse is that some ladies eat the male after the encounter - - that's gratitude for you!

Even though mites are small, their huge populations are mighty when potential plant damage is considered. These mighty small spider mites are often unnoticed by gardeners until the plant has been severely damaged. Spider mites flourish in hot, dry conditions. They are named for the webs they make on their host plants while feeding. Spider mites usually feed on the undersides of leaves and cause a stippled bronze coloration dotted with yellow specks, and webbing is usually present on the underside of leaves.

Gardeners respond by using carbaryl (Sevin). This often eliminates beneficial insects which consume spider mites and allow their populations to multiply rapidly. The mite is not an insect but rather related to spiders. They can only be controlled with a spider-killing miticide such as Kelthane or products containing kelthane. Add one teaspoon of a liquid soap per gallon of pesticide spray to insure good wetting of foliage and try to spray the bottoms of leaves as much as possible. When mites are detected, apply miticide spray every four days for four consecutive sprays. Since mite eggs hatch ever 3-5 days and since miticide sprays kill only the adults, consecutive sprays will hopefully destroy the young before they reach puberty.

Organic gardeners can use sulfur to control mites, but do not apply on squash or other vine crops. Other treatments range from permethrin sprays to insecticidal soaps to neem oil or orange oil products. Strong streams of water and liquid seaweed have also shown some effects on these tiny sapsuckers.

NOTHING works when populations are dense and weather is hot and dry. The best control is destruction of infested plant materials.

WEBWORMS


Webworms are back and there is NOTHING anyone can do about them---except let Nature take its course!

When the webworms begin, just stay in the house and wait for the populations to decline-which they will from year to year. Webworms have been written about and complained about for years with no apparent affect on the population. On March 21, 2004, it was announced http://bexar-tx.tamu.edu/HomeHort/F1Column/2004Articles/MAR21.htm that "The City of San Antonio, Texas Forest Service, Texas Cooperative Extension, Bartlett Tree Care and City Public Service have joined together to examine the effectiveness of releasing Trichogramma wasps into pecan trees as a way to slow down the rampant explosions of webworms seen in San Antonio over the past 2 to 3 years. Four city park areas will be targeted for this study with releases being conducted in mid to late April and again in mid to late June." That event yielded such inconclusive results (meaning that no one in their right mind could see any discernable differences in populations of webworms in the treated area!!!) that it was recommended again on May 30, 2004
http://bexar-tx.tamu.edu/HomeHort/F1Column/2004Articles/MAY30.htm
and yet again on June 20, 2004
http://bexar-tx.tamu.edu/HomeHort/F1Column/2004Articles/JUNE20.htm
Please do not waste your money on such a folly. Why is it a folly? No one denies that these wasps feed on webworm eggs but huge numbers of the wasps would have to be simultaneously evenly distributed over a massive area to see any significant population reduction. The release would have to be timed perfectly. A few folks doing releases in their own backyards amounts to a drop in the ocean or sort of like spitting on a forest fire! Left alone, these insects, as do all insect populations, will cycle and decrease in numbers after a population explosion has occurred. I have seen this happen with the diamond-back moth on cabbage, leafminers on peppers and thrips spreading tomato spotted wilt virus. Pecan trees have been surviving population surges of webworms for hundreds of years so they will survive our most recent problems. If only our population can endure the ugliness caused by tree defoliation and webbing.

I hope you will think about the "uncontrollables" in your landscape and not fall prey to the idea that you can man-handle Nature. For goodness sake, if you want to attack some of these insurmountable problems, don't waste your money on foolish man-made remedies. Saw the red-tip Photinias down, bury the spidermites, and burn the webworms out of the trees.

 

 


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