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 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.
The bane of pest control is a pre-mix of fungicides and insecticides often sold to home growers as “home orchard spray”. 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.
The theory is that mixing fungicide and insecticide together makes it easier for the home grower because there's less measuring than if you purchase separate fungicide and insecticide. The downside is that during most of May only a fungicide is needed for application.
It's best to purchase your fungicide and insecticide products separately so they can more wisely and safely be applied only when needed and according to the label. Most fungicide and insecticide products are tank compatible, They can be mixed together in a sprayer when both are needed. There are a few exceptions but not many.
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.
This 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 last minute protection.
A good example is controlling spotted wing Drosophila when raspberries and cherries are near the harvest stage. Since Malathion has a low PHI (pre-harvest interval), you can safely apply it closer to harvest. It's also 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.
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.
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.