Posted on by tonytomeo · 9 Comments

Horridculture – Pesticide

P90828Pesticides are a topic that I do not talk much about. There really is not much to say about them. Only a few are used at the farm, and only while certain destructive insects or perhaps mites are active. Even less pesticides are used in the landscape. It is not that I have serious issue with them. They are just not as useful for controlling pests as proper horticultural techniques are.

Plants that we would expect to require pesticides simply are not welcome in our landscapes. We know that snapdragons and hollyhocks are very likely to be detrimentally infested with rust. Therefore, we grow neither.

Roses live in some of the landscapes only because we do what we must to help them avoid infestation by the various pathogens that they are susceptible to. They get pruned aggressively in winter so that their new growth grows faster than aphid and mildew that try to infest them in spring. Their fallen foliar debris that fungal pathogens overwinter in gets raked away cleanly.

On rare occasion, we find weeds that we would like to kill with herbicide; but we can’t because they are too close to riparian environments. With two creeks and two streams flowing through here, many of the landscapes are too close to water. We must instead pull the weeds that we can, and hope that more aggressive cover crops overwhelm what remains before they recover.

One of the few insect problems that we sometimes notice is the thrip on the rhododendrons. They are sort of always there, but had been tolerable. Aggressive pruning to stimulate vigorous new growth, and also improve air circulation, should have inhibited the thrip. Instead, the damage has been worse than it has been in a very long time. It was necessary to spray insecticide.P90828+The pictures above and below show the worst of the damage caused by thrip. The picture below compares damaged foliage on the left to undamaged foliage on the right. Thrip rasp the foliar surfaces so that they can lap up the juices within. The process causes silvery discoloration, and ruins the foliage. Young damaged foliage is likely to get crispy around the edges, or get shed.P90828++For this sort of damage, I do not mind using insecticide. However, I have doubts about this particular insecticide, or whatever it is. It is supposed to be three in one; insecticide, fungicide and miticide. How is that even possible? Insects, mites and fungi are physiologically completely different. Anything that kills all three must be very nasty stuff! Yet, it is somehow safe for bees?!

There are several active ingredients, but I do not recognize many of them. I suppose that some could be insecticidal, some could be fungicidal, and some could be miticidal. The label does not explain the functions of the various components. None are hazardous enough to warrant a use permit like we need for agricultural pesticides. This product is available at the hardware store.

I do not doubt that this nonselective ‘pesticide’ is safe for bees, even though it is supposedly formulated to kill just about anything that might bother the rhododendrons. However, since it will not kill bees, and bees are insects, I do sort of doubt that this product will kill many other insects, including thrip.

 

Incidentally, I am sorry for the delay of posting my weekly ‘Horridculture’ rant, which should have posted yesterday. It normally posts on Wednesdays. The article that posted yesterday really should have posted today instead.

Posted on by tonytomeo · 15 Comments

Arachnophobia

70927lthumbsparePerhaps I should see this movie. I hear that it is pretty lame. I sort of wanted to see it because it was filmed in Cambria, about thirty miles to the northwest of where Brent and I were in our last year of studying horticulture at Cal Poly in San Luis Obispo at the time. Yet, I never select movies. I always leave that up to whomever I am seeing the particular movie with. None of my friends ever wanted to see Arachnophobia. The one friend who you would think would want to see it because of where and when it was filmed wanted nothing to do with it. You see, Brent, the famous horticulturist and landscape designer who works outside where spiders live, is afflicted with Arachnophobia.

About a year before the filming of Arachnophobia began, in early 1988, Brent lived in Sequoia Hall at Cal Poly to the north of San Luis Obispo, and I lived south of town, about twenty minutes away. Brent called me up early one morning as I was getting ready to leave for school to tell me about a spider in his dorm room. Perhaps “tell” is not the best word to describe his frantic panic. I mean, he was totally freaked out!

I told him to wake up Jerry, his roommate who usually slept in a bit later, and have him remove the spider. He got even more frantic and told me that Jerry was up in the room. Well, . . . if Jerry was up in the room, and Brent was not with Jerry, I just had to ask, “Where are you?!” “I’m calling from the payphone in the lobby!”, Brent explained frantically. (Telephones were hardwired in 1988.) Okay, so this complicated things a bit. He actually ran from the room and down from the third floor before stopping long enough to use a telephone? I told Brent that he should go back up to his room and have Jerry remove the spider. He really freaked out, and exclaimed, “Are you not listening?! THERE IS A SPIDER UP THERE!!”

Somehow, after explaining that Jerry did not answer the telephone when he had tried to call a few time before calling me, Brent convinced me to rush over and stop by before class to remove the spider for him. Brent was in his pajamas without slippers when I met him in the lobby and proceeded up to his room, where Jerry had just woken up to find Brent gone and the door wide open. We both went to the lower left sill of the window where Brent had seen the terrifying spider, and found it, dead. Yes. . . dead. I rushed over there, parked in a red zone, rushed upstairs, all to kill . . . a dead spider.

Well, it was not exactly a dead spider. It was the molted exoskeleton of a spider. In retrospect, I should have told Brent either that it was a dead spider, or that we had found and killed it. You see, Brent and I studied entomology together, so we knew how this molting process worked for certain insects. Arachnids like mites and spiders use a similar technique. As they grow too large for their external skeletal structure, they shed it, and then hide out somewhere while their new exterior hardens into a new exoskeleton. So when I told Brent that we found the molted exoskeleton, he freaked out all over again knowing that the spider was still hiding in his room, and that it was BIGGER!

I do not remember how Jerry and I got Brent to go home the following evening. Perhaps his second best option was to come to my house, where spiders were quite common. We never actually saw the spider.