From Tuber to Bloom: Part 2

You’ve done the work- you planted on time in the right spot. You fertilized, weeded, and supported your dahlia plants. But then, almost overnight, you notice someone is doing you dirty! You’ve got pests! You’ve got bugs eating your precious plants! What do you do???

Don’t fear! You can handle this. Dahlias are unfortunately subject to a lot of pests. The bugs like them just as much as we do. But over the years, I’ve developed some strategies to dealing with pests.

First you gotta’ get a gameplan:
1. Identify your pest— You can’t fight it if you don’t know what it is. Get your camera out and take some pictures. Photograph the bug itself if you can or take a picture of the damage. Both can help you identify it. Then you start researching. It helps to know a list of possible dahlia pests- gives you a starting point. These are the most common ones:
Thrips, Aphids, Earwigs, Cucumber Beetles, Japanese Beetles, Mites (Spider, Broad), Leafhoppers, Leafminers
Use these pests and combine it with words like - “leaf damage” or words describing the life cycle of the pest to find more information.
2. Know your pests life cycle. As if figuring out the pests wasn’t enough- you need to know the life cycle of the pests. Since a lot of insects go through different stages, you may need to fight them differently at different stages of their life cycle- fun huh?
3. Get a plan of attack. Once you know your pest and its life stages, you can formulate a plan of attack. Often you will have multiple stages of the pest in your garden at once. Which is why you may need to attack the pest several times to bring the population down. You may not completely eradicate it- which is not a bad thing because if you want good bugs to take care of your bad bugs— the good ones need some bad ones to eat!
4. Keep Records- Write down when you first saw a pest, what method you used to attack it, and also what the general weather conditions where around the time you first saw it. These will be handy in future years- you’ll begin to see patterns and it will help you predict when pests are going to show.

Once you have your plan of attack, make sure you are applying any spray properly—
Basics of applying pest control sprays:
1. Spray early in the morning or early evening
2. Don’t spray when it’s windy
3. Test the product on a small number of plants first
4. Don’t spray oil based products in high light situations
5. Read the product directions and take any recommended safety precautions.
6. Rotate the products you use- don’t use the same thing every time.

Also- consider preventing pests. When you first start growing you will be more on the other side and having to control pests once they’ve already arrived. But after a few years of growing, you may know their cycles enough that you can use prevention methods for some of them.
Consider prevention methods before applying a spray:
1. Timing- You can avoid some pests if you plant later or earlier in the season. For example, if you plant in May in my climate, Japanese beetles won’t bother your plants because they cause damage on the blooms. May planted blooms don’t bloom until August and the beetles are mostly gone by then.
2. Surround WP- This is a spray made of kaolin clay- it will turn your plants white but is useful to keep bugs at bay and also prevents powdery mildew. More info here.
3. Bagging Blooms- using organza bags on blooms can prevent bug damage, very useful on lighter colored blooms
4. Water- Using overhead sprinklers when hot can help prevent powdery mildew and also spider mites.

Commonly used sprays for Dahlias: (not all of this are listed OMRI(organic) so please read the labels before applying.)
1. Capt’n Jacks Dead Bug Brew- Spinosad based spray- not an immediate knockdown effect, takes 2-3 days to notice a reduction in pests
2. Bonide Maxx- one of the few I’ve found that helps with grasshoppers. (Encouraging your bird population still works better though)
3. Avid/Minx- miticides- use on mites. A lot of other sprays don’t work on mites and often you’ll need a specific miticide.
4. Pyrethrin- effective but don’t use if you know you have mites because pyrethrin can cause your mite situation to get worse.

Diseases— You’ll want to begin with the same process. Scout your plants regularly and take pictures. Research to figure out what you are dealing with and then formulate your plan of attack.
Common Dahlia Diseases:
1. Powdery Mildew
2. Verticillium Wilt
3. Viruses (several but a more indepth topic than we can discuss in this primer)

Powdery Mildew is fungal related so can be treated. Overhead watering is a great form of prevention. If you grow dahlias in a hot climate, there’s a good chance you will get it at some point. The goal is to prevent it for as long as you can. If you get it early in the season and leave it untreated, it can kill your plant. But if kept treated, your plant will usually survive until frost. We use the following sprays to keep it under control: Copper, Cease, Milstop.

We’ve really only scratched the surface here but these posts are meant to be a primer and a tool to help you get started on your dahlia journey. If you want more indepth, join us for Dahlia Bootcamp inside The Petal Society. It’s recorded so even if you missed the live event, you can watch it later.