The Yellow Farmhouse Garden

June 28, 2019

Getting back on track spraying fruit trees

Filed under: Disease,Fruit,Pesticides,Trees — Tags: , , — bob @ 3:11 pm

The almost daily rain we had this spring really put a damper on fruit tree spraying. Pesticides work best if they are applied at least 24 hours before a rain. When a rain happens before the next spray, the effectiveness is reduced as the material begins to wash off. Even a light rain can wash off a percentage of the spray. Heavy rain can remove almost all of the material allowing diseases and insects to get a foothold. So you can see how difficult is was spraying fruit trees this spring.

But now it looks like the weather has finally straightened out allowing us to get back on a regular pest control schedule. It’s too late to do anything about pests that emerged early but summer spraying can control later emerging pests like apple maggot, codling moth, peach tree borer and others.

Backyard fruit growers often use an all purpose fruit tree spray mix that contains a combination of insecticides and fungicides to control a wide variety of pests. It’s much more convenient to use and store a single container than a shelfful of assorted specialty materials.

All purpose sprays are applied as often as every week or two, or as few as twice a season, depending on the formulation used.

There’s a few things to keep in mind when mixing and applying pest control chemicals. These things are always printed on the label but in my experience,  I find that not everyone reads all of the fine print. A common mixing ratio is one or two tablespoons of product per gallon of water — that’s not very much. It’s tempting to pour in extra because it looks like that can’t possibly be a big enough dose to work, but it really is. Some people think they can approximate the ratio by pouring a quick dash from the bottle into their sprayer tank. I can guarantee that will always result in a much more concentrated solution than necessary. Always take the time to measure your materials carefully.

Adjust your sprayer’s nozzle to the most efficient spray consistency. A fine spray is more likely to be atomized, like perfume from an old-fashioned perfume bottle, causing it to be blown about even in a light breeze. You are more likely to inhale finely suspended materials in that case. On the other hand, a very coarse spray will not give you consistent coverage resulting in too much material in one spot and not enough on another.

Wait until the air is calm before spraying to avoid spray going all over the place except where it’s needed, including in your face. Early morning is best because the air is usually still and pests are at rest and have not started flying around yet.

Spray all surfaces of the tree leaves, don’t just make a spray over the top of the tree. Pests often spend time on the underside of leaves. And spray deep into the center of the tree. One major reason for pruning fruit trees is to allow sprays to penetrate into the tree without a lot of unnecessary leaf growth getting in the way.

To get the most protection for your tree, apply enough material until all leaf and stem surfaces are completely covered with adequate amounts of material. With all purpose sprays, that means until the spray just begins to drip from the tree.

Spray all surfaces to control hidden pests.

Spray all surfaces to control hidden pests.

I always try to mix just enough spray so that none is left over.  Any small amount that I have left over gets applied evenly over my trees until it’s gone. Both conventional and organic chemicals will lose their oomph if left in the sprayer tank for any length of time and can corrode, plug up or otherwise damage sprayer parts. Always rinse out your spray equipment right after each use.

Bob

 

June 8, 2019

Weather related disease problem on sycamore trees

The extra rain and cool weather we’ve been getting has been a mixed blessing. It’s June and a lot of gardens, farms and fields haven’t been planted yet because of saturated soil and cool temperatures.

On the other hand it has been great for established plants like trees and shrubs. In most cases they’ve made tremendous growth except for one notable exception — sycamore trees.

It’s quite startling to see how little progress the sycamore trees in our area have made. Most of them have very few leaves on them at all.

The maple tree on the left is flush with new leaves while the sycamore on the right is nearly bare.

The maple tree on the left is flush with new leaves while the sycamore on the right is nearly bare.

This is due to a disease called anthracnose, a fungal malady of sycamores that is present in varying degrees from year to year. This year’s outbreak is particularly severe due to unusual weather.

A lot of it has to do with timing. Rainy and cool conditions that occur a couple of weeks after bud break allows the anthracnose fungus to thrive. The longer that type of weather stays around, the worse the infection gets. That’s why our sycamores are looking so bad for so long this year.

There’s really nothing practicable we can do to cure or even prevent this disease.

Young leaves killed by anthracnose

Young leaves killed by anthracnose

Fortunately, once it gets warmer and drier they’ll bounce right back. Most of the time, very little major damage is done to the trees. The most obvious permanent damage you’ll see is “witch’s broom” a disfigurement of the branches that occurs in the spot the fungus killed twigs. At that point several small branches will grow from a single point giving it the typical witch’s broom appearance. Once the leaves fill out, however, the disfigurement is not so noticable.

Witch’s broom caused by anthracnose.

Witch’s broom caused by anthracnose.

Dead twigs eventually fall to the ground and can cause a mess in the lawn. This is probably why some people think of sycamores as messy tree, but it’s not the poor tree’s fault.

Trees can be sprayed or treated but it really doesn’t do much good since the infected parts can’t be healed anyway. Waiting for the weather is the best course of action in most cases. It extremely rare for a tree to die from anthracnose unless it is under stress from something else such as being planted in the wrong area or has a lot of bark damage from lawn mowers.

A little bit of fertilizer may help your tree to grow back its leaves faster. Generally, trees growing in lawns will get the nitrogen they need from the fertilizer used to fertilize the grass.

Anthracnose will always be with us so it’s just something we’ll have to live with.

Bob

 

September 7, 2018

Powdery mildew on cucumbers

Powdery mildew is a serious fungal disease of cucumbers and other related plants. It can completely wipe out an entire crop in a garden if nothing is done to control it. Regular rains, warm temperatures and high humidities this season have come together to make ideal conditions for powdery mildew development.

The standard method of battling this disease is applying fungicides of one type or another. Some are chemical, others are plant derived and there’s even bacterial fungicides. The drawback to each of these fungicides is that you have to apply them early when the plants are young and continue using them through the rest of the season. But there is another way.

Recently I had a chance to compare cucumber plants growing in two nearby gardens. Neither garden had any fungicide applied to them.

In the first garden, the gardener is growing a standard, run-of-the-mill variety of cucumber obtained from a garden department somewhere. The plants in that garden were nearly overwhelmed by mildew.

A non-resistant cucumber variety has no chance against mildew.

A non-resistant cucumber variety has no chance against mildew.

In the second garden, the cucumbers show little sign of mildew. That gardener opted to grow a mildew resistant variety from seed that he sowed directly in the soil.

A resistant cucumber variety stays healthy when other varieties fail.

A resistant cucumber variety stays healthy when other varieties fail.

The difference between the two crops is very impressive. If you are one of those gardeners who have given up on growing cucumbers and don’t like to spray fungicides, then planting resistant varieties is the way to go. Really, it’s something every gardener should look for when choosing cucumber seeds. Make a note of it in your garden journal as reminder for next year.

Bob

 

 

July 31, 2018

High temperatures can damage tomato plants

Last week I saw a lot of gardens having problems with tomato plants not producing fruit. When discussing this problem with gardeners, the first thing I hear from them is usually,” I’m growing lots of leaves but no tomatoes”. Then they go on to attribute it to an overabundance of fertilizer of one sort or another.

Nutrient imbalance may cause problems, but this season it is likely due to the extended hot temperatures we had until the break in the weather happened this week.  Temperatures in the mid-nineties can damage tomato blossom causing them to fall off the plant — no blossoms means no tomatoes. This phenomenon is known as “tomato blossom blast”.

Heat damaged tomato blossoms turn brown.

Heat damaged tomato blossoms turn brown.

There is really nothing we can do to prevent flower damage when the temperatures are so high except wait it out. Now that the weather has moderated, our tomato plants will start producing more blossoms and setting more fruit.

If another heat wave occurs, it’s likely we’ll see another round of tomato flower blast.

Bob

 

November 16, 2017

Three impressive tomato varieties

Filed under: Disease,Vegetables — bob @ 12:12 pm

Earlier in this past growing season I took an informal survey of how a number of tomato varieties were responding to leaf spot diseases. You can go back and read the post to find out how things were going for them at that time.

I kept an eye on them through the season and watched their progress. In one garden I applied a couple of sprays of an organic fungicide, that didn’t seem to make much difference; it may have helped if I kept it up. As expected, on all of the plants, sprayed or not,  the leaf spot symptoms got progressively worse as the fruit on the plants began to grow and develop. It takes a lot of plant energy to produce a crop of tomatoes.

A curious thing happened on one variety at the end of the season. The heirloom variety, Granny Cantrell, began to shake off the fungal infection. While the other tomato plants lost pretty much all of their leaves and most of them actually died back, the Granny Cantrell plants shed their infected leaves and grew very healthy looking replacement leaves. That was something I’ve never seen in a tomato plant. Sure, many varieties struggle to send out more leaves but they never seem to amount to much. Not only were they growing leaves but they were also ripening existing fruit and producing new tomatoes to boot! Our growing season is too short for the plants to continue to grow so I’ll never know if the new shoots would have continued to grow without leaf spot symptoms. It may be a useful trait that tomato breeders could use to develop a new variety.

Notice the new green foliage on the Granny Cantrell plant on the right compared to the defoliated tomato on the left.

Notice the new green foliage on the Granny Cantrell plant on the right compared to the defoliated tomato on the left.

Juliet was another noteworthy tomato. They had good resistance to the diseases throughout the growing season and produced a huge crop of tomatoes, far out pacing any variety I grew this year.

All of the tomatoes I grew were tasty, how could they not be? since they were vine-ripened and eaten right after picking. All the people who tasted the tomatoes; and there were quite a few, agreed that Cherokee Purple was their hands down favorite. Cherokee Purple however,  had little disease resistance and didn’t produce very many tomatoes at all. They also have very thin skin making the very hard to handle without damaging them. They are not a typical red tomato so their coloring made it harder to distinguish when they were ripe. Also their flesh inside has a distinctive purple hue that, along with their taste makes the quite memorable.

Bob

 

 

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