Pests, Varmints, and Disease

When bad things happen to good plants

If it hasn’t happened yet, it will.

Your plants are doing nicely and then disaster strikes. Your plants have been nibbled, gobbled or are just looking very sad. Dead, even.

And let’s face it, a quick fix is an appealing response. But before you reach for the chemicals or even organic-approved remedies, it can be well worth it to pause first and do some research.

Here’s a common example.

Your lush tomato plants have a bare spot with just stems remaining. Looking closely, you see the telltale caterpillar droppings. You stand and stare and then you see it, perfectly camouflage against the lovely green leaves, munching away happily. Or dozing and dreaming of his next meal of delectable tomato foliage. 

Meet the tomato hornworm. He has a voracious appetite for your tomato plants and can be almost as large as your index finger. He can clear a large area of foliage from a plant in a day and will even eat his way across a green tomato if it is in his path. And wow, can he ever hold onto the vine. 

There are several things you can do about this pest, but it is important to pause before you reach for the insecticide. There are many pests that will trouble your garden and it is important to make sure that the solution isn’t causing problems as well. 

BT (Bacillus Thurengensis aka Thuricide) is an effective way to kill tomato hornworm caterpillars. It is approved for organic gardening, why not? 

1. It has not been well proven that BT does not affect the human digestive system
2. BT seems to disorient bees that happen to ingest BT 
3. The tomato hornworm grows into a Manduca quinquemaculata (hawkmoth, aka hummingbird moth which feeds on nectar and thus serves as a pollinator)
4. In killing this one tomato hornworm, you may be killing parasitic wasps that would go on to get rid of many tomato hornworms
5. There are are easy ways to control the problem without using pesticides. 

My gardening motto is to always go with the least intrusive approach first:

In the case of the tomato hornworm, you have several options:

1. Before you do anything at all, observe the caterpillar closely. If you see little white protrusions, you should leave the caterpillar alone. These white spots are parasitic wasp eggs. If allowed to hatch, they will develop into more such insects that will target and kill other hornworm caterpillars and pests in your garden.This caterpillar will not live long if it is covered in parasitic wasps. 

2. Spraying with BT is definitely an option. 

Spraying in the evening may be helpful as it will help to avoid bees getting into it.

Spraying the caterpillar won’t do anything at all. They must eat it, so spray out ahead of the caterpillar as he eats as he goes.

3. Handpick the caterpillars - they hold on tight. I usually just clip off the stem they are on. You can try to relocate them to another nightshade plant, such as tomatoes or tobacco that you have started far away from your garden for this purpose

4) If you are not averse to killing them, you can feed them to your chickens where they will be greatly enjoyed and provide an important food source. Or you can simply drop them in a bucket or water with a few drops of dish soap stirred into it. 

Another pesky pest is the Cabbage Looper. Similar to the tomato hornworm, it feeds on your cruciferous vegetables (broccoli, kale, cauliflower, rutabaga, brussels sprouts) while in its larval form. If you do nothing, the loopers will devour your plants. 

The worst part is that they will also show up on your plate and that is just not fun.

Before BT, there was no organic solution and my dad was organic before organic was cool. My mom used to soak the affected vegetables in 1-2 TBSP salt in a gallon of water in a large bowl. The salt made the loopers float to the surface so they could be removed. This method works pretty well, especially if you cut apart large heads of broccoli or cauliflower so the worms are easily freed from between the stems.

There are a couple things you can do about cabbage loopers:

1. Grow your cruciferous vegetables under lightweight floating row cover. The moths can’t fly in and lay their eggs which develop into caterpillars.  This has the disadvantage of being made of spun polyester which is being shown to leave behind microplastics. It also can be rather a nuisance to remove the cover to weed or harvest or check the plants.

2. Use a BT spray on your plants about 1x week as soon as you see damaged leaves. This is my method of choice. It is much simpler than row cover and very effective. Remove flower heads (ie broccoli and cauliflower, for example)  before they open or stop spraying. Avoid getting BT spray on other flowering plants.

My honeybees love broccoli flowers and I don’t want them eating BT tainted nectar or worse yet taking the pollen home to feed their larvae. It makes sense to me, although I haven’t yet researched it, that what destroys the digestive system of one larval form of insect (such as  tomato hornworms and cabbage loopers) would also damage my honeybee larvae.

Either of these solutions has drawbacks. It is up to us to decide which to employ and to continue to do our research for new products, new information. 

Varmints 

Here in the northeast, the most troublesome “critters” are:

It can be helpful to use odor repellants, but they must be repeated frequently especially after the rain. The best solution I have found is putting up a second fence (not necessarily electric) about 4’ outside of the electric fence. My understanding is that a deer will not leap if there is not a clear landing on the other side. This has worked well in my garden, although it causes inconvenience to mowing. 

Woodchuck who is sometimes stopped by a garden fence Good garden hygiene is important to deter this pesky pest. He does not like to be out in the open so well mowed areas are not his friend. A garden swamped in weeds provides a lot of hiding spaces. 

One year I saw this woodchuck with her four little (extremely adorable) babies. I decided to leave them alone and I had a big problem for years afterwards. They destroyed my garden completely for two years. One day in exasperation, I fell upon a solution. 

I was outside carrying a bucket of used cat litter to dump it where it could decompose. I almost stepped into a new woodchuck hole. I was so annoyed to find yet another burrow entrance. I upended the bucket of stinky litter right into the hole. He never redug it. And by the end of two more years I had discouraged most of them off my property. I still have trouble occasionally, but keeping things well mowed and treating the holes with cat litter is very helpful. 

Voles are similar in appearance to mice. In the garden you see small holes in the ground and chewed plants nearby. They are not easy to trap. Here is the solution. You bait a snap trap with peanut butter and set it a few inches from the hole. Then cover the hole and the bucket with a pail or over cover so the trap and hole are in the dark. Check daily.  Toss the rodent out of the way or into the compost. Be persistent until you see no more damage. If you close holes as you go, you will be able to see what ones are still in use.

Please do not use poisons to get rid of small animals on your property. It takes a long time to kill them with poison and it ends up in the bellies of raptors who have a rough enough go of it without being slowly poisoned by ineffective ways of getting rid of rodents. 

What pests are causing problems in your garden? Drop a line. Ask a question.

Sources:

Are all forms of Bt toxin safe?
Tomato Hornworm