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Municipal Services
March 6, 2000

Best Pesticides For The Home Orchardist

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Best Pesticides For The Home Orchardist

So many people want to grow fruit these days but don't know which are the best pesticides and when to use them. It is fun and exciting to plant fruit trees and then wait in anticipation for the delicious fruit crop they will produce. Sadly, people are not the only life form that enjoy all the fruits you so carefully nurtured in your home orchard. Many insects and fungi find your fruit or fruit trees attractive too. Unless you plan on growing your fruit in bags for organic control (cloth, paper or plastic), you most likely - at some point - resort to chemical control to get a decent fruit crop.

Gone are the days when people didn’t mind if their home fruit crop was wormy, insect riddled, fungal infected etc. and would just cut out the damaged sections of their fruit and salvage what they could. We can now do better. There is no reason why your homegrown fruit cannot be as perfect as what you can buy from a commercial orchard or supermarket.

How Often Will I Spray?

How often you will need to spray and what product you use is up to you. It will depend on how much time you want to allocate to this task, how much insect/fungal damage you are willing to accept (or not) and what the weather is for that growing season (weather often can play a large part in the severity of many fruit diseases).

You don’t want to spray? Then consider going organic and growing your fruit in bags. Willing to spray but not too often? Then try and hit the KEY times to spray for prevention of a major pest issue. In the case of apples, they key times are May and June (Primary apple scab, plum curculio, leafrollers, 1st generation codling moth, cedar-apple rust). The second key time on apples is for apple maggot (historically the peak flight is in August). So, the key times for apple pest control would be to spray all of May—June and then once in early August. Will this give you perfect fruit? Possibly not, but it should give you a crop of decent apples most years (depending on the severity of sooty blotch, fly speck & second-generation codling moth).

For those who want perfect fruit, then it is more critical to follow a spray chart or monitor the insect/disease possibilities (monitor degree days, amount of rainfall, check insect traps etc.) and then spray when needed.

What spray chart and what to spray? This topic is perhaps the most misunderstood by the home fruit grower. Fruit spray charts are put out by numerous state universities and are tailored for their specific fruit growing region. Yes, different regions of the country have different fruit insects or disease pressure.

Below are some simplified versions of spray charts for apples, cherries, peaches and plums that are suited for home growers here in Wisconsin. Also below are some of the best pesticides available and work well for the home orchardist.

Avoid Pre-mix Fungicide/Pesticide

The bane of pest control is a pre-mix of fungicides and insecticides often sold to home growers as “home orchard spray”. The theory is that having the fungicide/insecticide mixed together in one product makes it easier for the home grower as less measuring to do than if purchasing separate fungicide and insecticide products and only one product to purchase! The downside is that during most of May only a fungicide is needed for application. Spraying one of these pre-mix products in May can really harm the bees if used during or near blossom time because they also contain an insecticide! Best to purchase your fungicide and insecticide products separately so they can more wisely and safely be applied only when needed. Most fungicide and insecticide products are tank compatible and can be mixed together in the sprayer when both are needed. There are some exceptions to this but not many.

Fungicides & Insecticides

1. Captan 50 WP and/or Spectracide’s Immunox. Immunox (active ingredient: myclobutanil) will provide protection against cedar-apple rust while Captan will not. Use Immunox if rust has been a problem on your apples. Rust prevention needs to be applied in mid-late May. Both these fungicides work well for preventing apple scab. Both products are listed for apple, cherry, peach, plum and grapes. Myclobutanil is very rain fast so excellent to use in May when rainy weather is frequent (applying both Captan and myclobutanil together in the tank mix when forecast is wet in spring provides great apple scab protection). Apply either one or both of these fungicides when spraying as conditions warrant.

2. Ortho Flower, Fruit and Vegetable Insect Killer. A good insecticide for the home grower. Be sure this product lists Acetamiprid (0.5%) as the active ingredient on the label before purchasing as Ortho has some similar sounding products too. I have used this product for the past several years on some of my apple and sweet cherry trees as a test and it works very well. Acetamiprid is also commonly used by commercial orchardists who can buy it under a different trade name. Ortho’s product comes in ready to use spray bottles or in a 32-ounce concentrate. The concentrate is the way to go for spraying apple trees (sprayer required).

3. Malathion insecticide has been around for years and was commonly used in the past on home fruit orchards. While this product does a fair job on many fruit pests (except curculio) it has an extremely short residual. The ½ life is 4 days. To maintain good insect control on apples one would have to spray every 7 days. Due to the short residual activity it still is a good insecticide to have if you have fruit that is almost ripe but needs protection for a short time. A good example is controlling spotted wing Drosophila on raspberries and cherries when they are almost at harvest stage since it has a very low PHI (pre-harvest interval) so can safely be applied very close to harvest. It also is reported to work well on brown marmorated stink bugs which are just becoming a problem in Wisconsin (and can be an issue on apple crops). Wise to keep this product in your fruit arsenal for when appropriate.

4. Bonide Fruit Tree and Plant Guard. This is a pre-mix containing an insecticide (lambda-cyhalothrin) and 2 different fungicides (Boscalid and Pyraclostrobin). Lambda-cyhalothrin is a synthetic pyrethroid that controls many different insect pests.

Chlorothalonil

There are numerous fungicide products on the market containing the active ingredient: Chlorothalonil. These products are used for fungicide prevention on stone fruits (peaches, cherries, plums etc.). They are also commonly used by anyone growing tomatoes to prevent early blight. Any fungicide product containing this active ingredient and listing on the label rates for stone fruit crops can be used to prevent blossom blight on cherries and peach leaf curl on peaches (apply when tree is still dormant). Beware however that the label will state that Chlorothalonil can only be applied on stone fruits at dormancy stage up to shuck split stage of fruit development (occurs shortly after petal fall). It can also be applied (if needed) after fruit is harvested for prevention of certain fungal issues on stone fruit foliage (cherry leaf spot). Chlorothalonil works very well on the prevention of peach leaf curl. These products can be purchased online or from your local chemical supplier. While at a local chain store, I found 4 different fungicide products available containing chlorothalonil. All had different product names (manufactured by Bonide, Ortho and Ferti-lome). The price differed for each product. I have tried 3 of the 4 different versions over the years and they have worked equally well for me.

Paul's Apple Spray Guide

Leaves first open in spring 1/4” -1/2”
Spray fungicide for apple scab prevention

7 days later
Spray fungicide for scab/rust prevention

7 days later
Repeat above again unless already at petal fall stage

Petal Fall
Spray fungicide + insecticide for scab, plum curculio, leaf roller

7 days later (1st cover spray)
Spray fungicide + insecticide for scab, plum curculio, leaf roller

7 days later (2nd cover spray)
Spray fungicide + insecticide for scab, plum curculio

Continue spraying every 7 days up to June 15th. Since primary apple scab season is now usually over and Plum curculio season is winding down we can switch to a summer spray schedule:

June 15th-late August
Spray fungicide + insecticide every 14 days for apple maggot, coddling moth, sooty blotch, fly speck, summer fruit rots

Stop spraying sooner if your apple variety ripens in July, August or early September. See the PHI (pre-harvest interval) listed on the pesticide label. This will tell you how many days the product can safely be applied before harvest. Always follow the rate and directions listed on the label.

Paul’s Prunus Spray Guide

Cherry

White bud stage
Spray Captan or Chlorothalonil for blossom blight control

Full Bloom
Spray Captan or Chlorothalonil for blossom blight control

Petal Fall
Spray Captan or Chlorothalonil + insecticide for plum curculio, leaf spot, blossom blight

Petal Fall
Spray fungicide + insecticide for scab, plum curculio, leaf roller

First cover spray (10 days after Petal Fall)
Spray Captan + insecticide for leaf spot, plum curculio, fruit fly

Additional cover sprays every 10-12 day until harvest

NOTE: Captan and Malathion can be sprayed up to 3 days before harvest if brown rot and spotted wing Drosophila are an issue.

Peach

Dormant spray (late winter-early April)
Spray Chlorothalonil or liquid copper for peach leaf curl

Petal Fall
Spray Captan + insecticide for blossom blight/plum curculio

First cover spray (10 days after petal fall)
Spray Captan + insecticide for plum curculio, fungal issues

Second cover spray (10 days later) and repeat every 10/12 days up to early July.
Note: If brown rot is an issue, Captan can be sprayed up to 3 days before harvest

Plum

Dormant spray (late winter/early spring)
Spray Chlorothalonil for black knot

White Bud stage
Spray Captan for black knot/brown rot

Full Bloom
Spray Captan for black knot/brown rot

Petal Fall
Spray fungicide** and insecticide for brown rot/plum curculio

First cover spray (7 days after petal fall)
Spray fungicide** and insecticide for brown rot/plum curculio

2nd cover spray (7 days later) + subsequent sprays (every 14 days)
Spray Captan + insecticide

**Captan fungicide may russet the skin of certain plum varieties when applied early in the season when fruit is still small.