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Integrated Pest Management (IPM)
The IMP Strikes Back

by Jerry Yoneda


This Series of 'Jerry and June' articles was written to show that there is more than one way to perform each and every task in rose growing. The format is a humorous dialogue between two members of the Utah Rose Society, who have VERY differing views on rose growing. With a bit of experience, The novice will eventually develop his or her own unique way of growing roses. As the old adage says: "There is more than one way to skin a cat". And from the point of view of the long term rose grower "...if it ain't broke don't fix it."


Jerry: Well I'm here to discuss I.M. Pei with you, but personally I like the work of Orville and Wilbur Wright better.

June: I'm sure you meant to say that you like Frank Lloyd Wright, didn't you?

Jerry: No I meant what I said, if it weren't for the brothers I would be driving to Portland next week. My only question is what architecture has to do with our article.

June: Well for one thing I asked you here so we can write an article on IPM.

Jerry: Aren't those the guys that are managing the business careers of those athletes like Arnold Palmer and Tiger Woods?

June: Enough already, since your program at last month's meeting was on spraying roses, I thought we should let the people decide what level of protection to use in the gardens by discussing the principals of Integrated Pest Management, IPM.

Jerry: You know how I feel about this war of attrition stuff, I grew up during the Vietnam War. I say we "nuke em!" and finish it once and for all. The next thing, you'll be asking for an insect body count to see if you're killing enough insects at each step, and if not you will then escalate to the next level of attack!

June: We both know that you like to ridicule everything you're against to the point that you think you will win the argument by making people so tired of all the crap that they give up.

Jerry: Well if that's true then I do understand stand IPM because I wore you down didn't I. Just kidding, I promise to let you inform people about IPM without too much interference from me. But why did you need my assistance anyway?

June: Because in all cases the final step in the management of the pest is the most stringent control, usually spraying, and since I do not spray I need your assistance in what the latest and greatest sprays are. So what we will do is discuss each of the most common pests in turn and go from the least toxic to the most toxic way of controlling the pest.

Jerry: Okay, "let's start at the very beginning, a very good place to start". If it's ĎA', its aphid. So now do your part.

June: The first and most innocuous control of aphids is to wash them off with a stream of water.

Jerry: Actually the first step should be squishing them with your fingers. The brown aphids leave a nice stain on your hands.

June: Personally I prefer to skip that step. So if the stream of water does not cure your problem, you can buy biological controls such as: ladybugs, lacewings, praying mantis, and wasps. I really like the wasps because they paralyze the aphids and inject their eggs into the paralyzed body, after the eggs hatch, the larva eat their way out of the body leaving an empty carcass with a hole in it.

Jerry: Does that work or just give them religion?

June: How would that give them religion?

Jerry: Well now you have the three prerequisites; the father, the son, and the holey spirit.

June: Forget I asked. Now tell them about spraying for aphids.

Jerry: Yes, boss! The most innocuous spray and usually a very effective one is to use insecticidal soap to smother the aphids. And if you choose the big stick, hammer them with diazinon.

June: Next we have blackspot. First try to prevent overhead watering of your bushes, and if you must water try to water early in the day so the leaves will dry out before nightfall. Next around the first of June you can strip the lower leaves from the bushes this helps prevent both mites and blackspot because this is usually the point of initial attack. Now you can tell them how to spray for blackspot.

Jerry: Before that we should say good housekeeping helps. Blackspot overwinters in the garden so either in the fall or at the time of pruning all residual leaf refuse should be removed from the yard. Some success has been achieved by spraying with antitranspirant material such as, 'Cloud Cover'. The theory is that these materials form a hard coating on the surface of the leaf, thereby preventing the spores from penetrating the leaf surface. Some Californians are claiming that the use of Miracid helps prevent blackspot, but no one knows why. It could be that by improving the growing conditions of the plant, fertilizer and a more optimum pH, you are improving the roses natural defense system. There has also been some sucess on spraying with baking soda (1Tbs/ Gal). The only precaution I would tell those people trying this is not to soak the ground. Baking soda will form insoluble heavy metal carbonates with several of the trace elements i.e. iron, manganese, and zinc, which would become even more impossible than the insoluble oxides that form in our alkaline soils for the plants to take them up. Finally my favorites: the chemical sprays. Starting in June if you are on a weekly spary schedule alternate a mixture of Funginex/Daconil with a Funginex/manganese zinc fungicide (Maneb, Mancozeb, Rally, etc) mixture. If you are on a two week spray cycle with Banner Maxx, mix it with one of the aforementioned manganese/zinc fungicdes.

June: I would also advise against buying field grown roses from California. I never had any black spot in my yard until I did.

Jerry: Actually you should dip these roses pot and all in a 1% bleach solution (1/4 to 1/3 cup in a 4 to 5 gallon bucket) the same as any bare root roses you purchase. In fact I got downy mildew into my garden the very same way. And it is a much more insidious disease in that it will not just defoliate your plant but kill it outright,

June: What is the best way to tell the difference between downy mildew and blackspot. Sometimes it's difficult to tell the difference between black and dark purple spots.

Jerry: Probably the simplist way is that downy mildew will attack young growth, and blackspot old growth first. In fact downy mildew is next on our list.

June: First off until recently downy mildew was very rare in the garden. It was mostly a greenhouse disease, then it got into some of the growing fields of California and has started to appear in home gardens. The only non spraying treatment I know of is heat. In a greenhouse it is easy enough to heat a greenhouse sufficently to kill the disease. The only article I have seen about using heat in the garden is the one in the newsletter acouple of years ago. This treatment involves hooking up a hose to the water heater and spraying a bush until it just begins to steam. I would be extremely careful if I was going to try this method, and I would experiment on one rose bush, preferably one you don't like, before I tried it on the whole garden. Jerry, what type of chemicals are recommended?

Jerry: The chemicals used to treat downy mildew come in large sizes and are quite expensive since they are mainly for the commercial grower and not the home gardener. So if you have your downy mildew confined to a small area you might consider shovel pruning the infected plants. If you are inclined to spray as a preventative measure do so when the whether just begins to warm but is not hot (late May to early June in our area). According to the Consulting rosarians manual, Texas A&M University found that treatment required a surface (daconil) and a systemic (ridomil) component. Currently a product called Subdue has become prefered treatment. I had success in eradicating the disease in my yard with the daconil/ridomil treatment. I stopped spraying after using the mixture twice a year for five years and have not seen the disease in the subsequent two years. But as I said they come in large sizes. I had to buy six pounds of ridomil.

June: Next on our short list of typical pests in Utah is mildew. I just remembered the first thing to try to prevent any pest attack is to avoid planting a large concentration of any one type of plant. Of course since most of us are into roses that may not be practical. But it will also help to reduce fungus problems especially mildew if you have good air circulation. This can be acheived by proper siting of plantings along with wider spacing of the roses in our gardens. Some rosarians are claiming that the spores migrate during early afternoon and can be washed off with a spray of water every evening. Care should be used not to carry this treatment into blackspot season i.e. when the temperatures get above 90 o F. The least toxic of sprays are again antitranspirants and baking soda.

Jerry: You can try to prevent mildew by using funginex weekly or Banner Maxx biweekly. But since these are just prevent the disease and do not fight it, if you do get a mildew attack you will need to spray with an eradicant such as Systhane or Rubigan. I have had good sucess in spraying every other week with funginex and then a funginex/Rubigan mixture, or spraying every two weeks with a Banner Maxx/ Rubigan mixture. However, if you do not require a lot of spray material Systhane is supposed to be as effective and comes in a smaller sized container and is also the fungicide in Immunox.

June: No we come to the pest, spider mites, that is so devestating in such a short time that some IPM gurus go straight to the use of Avid on them. Mite attacks may be lessened or prevented by stripping your roses of their lower leaves in late May to early June. The first line of defense is by washing off the mites from the bottem of the leaves where they reside, with a waterstream . This should be done from the bottom of the plant. Next you can by predator mites to control the mites.

Jerry: The most effective miticide, Avid, is not only approved by IPM proponents but also by several organic gardening proponents because it is a natural product extracted from the soil. It also has the advantage in that mites do not seem to build up a resistance to it. The effectiveness of miticides is improved by Stirrup M, which is a pheremone that attracts the mites to the miticide. Since Avid is systemic you do not have to get it on the undersides of the leaves as you do with fungicides and some insecticides.If you have a severe attack it is recommended that you spray three times on three day intervals to kill all the mites and the eggs that hatch. Of course since Avid is suppossed to be systemic this might be overkill. Sice mites are so devatating I begin preventative spraying the first of June and spray as long as the weather remains hot. Another effective miticide is Vendex (good for 28 days), it comes with Orthene in Isotox.

June: Finally we get to the ubiquitous thrips. Thrips tend to discolor bloom tips and sometimes cause floweres to ball. They appear to attack pastel flowers first. You can minimize thrips attacks by removing other flowers they like such as dandelions and iris. Or you can live with discolored pastel roses or buy darker colored roses.

Jerry: I'm suprised you have not gone into your neighbors yards to attack the dandelions. Well this is another pest that I preventative spray for, once the dandelions and iris quit blooming they head for the roses. So I do a preventative spraying of orthene at this time.

June: One stage of the thrip life cycle can be controlled by using diazinon on the ground and the other stage by spraying open flowers with malathion. I prefer to spray Orthene on the plants. Since Orthene is a systemic it begins to control the thrip as soon as they start feeding on the unopened blooms.

Jerry: Well now that we're done I'd like to say that your neighbor over there has some pretty good architecture.

June: Oh no, not that again! Where are you going now?

Jerry: To the restroom, I am pee.

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