In this week’s newsletter we discuss how we manage some pests without the use of pesticides. How cool is that! But first a couple of announcements.
Still taking order for shares. Send more people our way!
Same for other items: Coffee, Mushrooms, Eggs (yes, we have enough orders to add another case of eggs), etc.
Still thinking of starting the week of June 17th but stay tuned.
Farm News
It seems we have entered into a period of on again/off again rain. It makes farming a bit challenging — but then again what doesn’t make farming challenging? The biggest issue with frequent rain is the soil never dries out enough for us to tackle the weeds. And the weeds love the moisture so they grow exceptionally fast! And of course this time of year we are still trying to get the remaining plants planted (though that continues even into the summer and fall but certainly not at the current pace) and having wet soil prevents us from doing it. So when we get a string of dry days we have to work quickly to accomplish as much as possible before the next rain comes. Such is farm life.
Other than planting and watching weeds grow we are also now having to deal with pests. I saw flea beetle damage on some of our brassicas. I also noticed a few cabbage butterflies flying around so I suspect they are looking for a little butterfly hoochie-coochie. And we all know from childhood what the consequences are of butterfly hoochie-koochie — a very hungry caterpillar, or more likely many very hungry caterpillars.
Which brings me to today’s topic (what took you so long?): pest management. Since we grow organically we only use organic approved pesticides. But I should point out that using pesticides is a “last resort” in trying to manage pests. We have a number of ways to manage pests (including weed pests) that don’t involve spraying pesticides. Let’s take a look at a few now.
As I mentioned, one of our frequent pest visitors are the flea beetles (not to be confused by the more musically talented beneficial insect, The Flea Beatles). These pests overwinter in Minnesota despite their ability to fly (they are not the brightest of the insect pests) so they emerge when it warms up in the Spring. They eat members of the brassica family — cabbage, broccoli, cauliflower, etc. They seem to prefer bok choy above all the other brassicas — though Napa cabbage is a close second. They chew many small holes in the leaves of the plants which renders the plants unappealing (though still edible). Sure we could spray organic pesticides to try to kill the flea beetles but it is impossible to kill them all — and the organic pesticide we would use isn’t 100% effective and must contact the beetle to kill it. And since the part of the bok choy we eat is the part that the flea beetles eat/damage — the leaves — keeping flea beetles off the bok choy is more important than say keeping them off the broccoli where we consume the flower head and not the leaves.
We keep the flea beetles off the bok choy plants with a floating row cover (see picture above). A floating row cover is a lightweight spun fabric that “floats” over the plants. It doesn’t require support since it is so lightweight. Then we hold down the edges of the fabric with wooden boards “sealing” the edges so that flea beetles can’t get to the plants. We leave the row cover on until we are ready to harvest, then only expose the plants we are harvesting.
In the olden days before we got a plastic mulch layer we would leave the bok choy to fight the weeds by themselves. If we removed the cover to hoe the plants flea beetles would have access to the plants and we couldn’t eliminate them all prior to putting the cover back on. It effectively defeated the whole approach. So the plants competed with the weeds and for the most part were fairly successful. However now with our ability to lay down a weed barrier prior to planting and covering we’ve given the bok choy a greater chance of success. Since bok choy is a cool season crop we don’t want to use black plastic due to its ability to heat up the surrounding environment. Conveniently there is also white plastic available for use in these situations. So we put down a layer of white plastic, plant the bok choy through the plastic then cover them with the row cover. It is a pretty involved process but eliminates the need to spray the plants with insecticide.
What is the downside? One of course is cost. The row cover rarely lasts more than one time before it tears. There is also the cost of installing and removing the plastic and the row cover but that might be offset by eliminating the hoeing and spraying. A second, greater downside is pest related. We rarely have aphid problem on the farm due to the large number of ladybugs. Ladybug larva are heavy consumers of aphids. However, if aphids get under the row cover they can quickly multiply since the cover prevents ladybugs and their kids from getting to the aphids. The aphids attack the bok choy and typically damage it beyond what we consider acceptable. We see this every so often and typically only in a small area under the cover. I’m not sure how the aphids get under the cover. I suppose they were on the plants prior to planting? Who knows. But this shows that every approach to pest management has drawbacks.
We use a similar approach for Swiss chard, though in the case of chard the pests are the deer (though we’ve also occasionally had unknown insect problems on the chard). Much like the bok choy, we lay down white plastic, plant the chard through the plastic but then cover it with plastic mesh instead of floating row cover. We have to use hoops to hold the mesh above the plants otherwise the mesh would tear the chard leaves. We could do without the white plastic if we wanted to hoe. Removing the mesh then reinstalling it takes a bit of time but unlike flea beetles, deer don’t suddenly show up when the mesh is removed. And if they did we would quickly realize they were there and could implement some other tactic make them feel unwelcome.
Wow, that is a lot of words already and I’m just getting started! Maybe I should save other pest management practices we employ for future newsletters. That way I won’t have to keep thinking of new topics each week!
As always, do not hesitate to send in questions, comments, suggestions, jokes, orders, or anything else you deem worthwhile.
Joke of the Week
A lonely old man decides to get a pet caterpillar. He takes the pet caterpillar home and sets up a cage for him. The next morning, the man goes up to the cage and asks the caterpillar, “Hey, would you like to go out to breakfast with me?” The caterpillar does not respond. Lunch comes around and the man again goes to the cage and asks, “Would you like to go to lunch with me?” The caterpillar still does not respond and the man walks away sad. Dinner comes around and again, the man goes to the cage and asks, “Hey would you please like to go to dinner with me?” To which the caterpillar responds, “I heard you the first time! I’m putting on my shoes!”