Gregory's ServerHow does Pierce's disease spread? This little punk, the glassy-winged sharpshooter.
They're pretty common! They feed on the sap from plants and trees.
Sap doesn't have a lot of nutrients, so they have to drink a LOT of it to get enough energy.
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A lot of muscadines have a thick skin and seeds- especially older varieties. That was also true of Old World grapes until pretty recently! It took a lot of selective breeding to get thin-skinned seedless grapes. We're getting there with muscadines too. Ok let's talk about Old World grapes, Vitis vinifera. They were domesticated in the Middle East, Caucasus Mountains, and/or west Asia. That means unlike southeastern muscadine grapes, they like dry weather! They're a popular crop where water's more scarce. Because they like dry weather, vinifera grapes tend to get pests that like dry weather too. They've got a whole different pest spectrum than what we usually deal with in the humid, soupy South. For example: spider mites. They're called that because they like to make webs. 🕸️ We don't get spider mites very often in the South. As soon as it gets wet they get wiped out by fungal infections. So they usually don't last long here 🤠 You need a nice, long, hot, dry dusty stretch to get a proper outbreak of spider mites. Heard of insects getting resistant to pesticides? Mites do that too- and FAST. So figuring out how to control mites without pesticides became a huge priority for vineyards. Not "just" for sustainability reasons, but bc pesticides just plain stopped working. The good news: there are lots of things that eat the mites that eat grapevines. 1. Bigger mites! 2. Ladybugs have tiny little relatives called SPIDER MITE DESTROYERS. Look at them. You gotta bring the results to get a name like that when you're less than 1/8" long. Spider mite destroyers are so hungry, they'll eat every mite in sight & fly away. Predatory mites take a little longer to get pest mites under control. But once they're in your vineyard, they stick around. Here's the challenge with using predatory insects to eat pest insects. Insecticides kill the predatory insects. So to make biological control work, you HAVE to stop spraying most/all insecticides & miticides. Biocontrol: works great, but it'll get worse before it gets better. Most vineyards in the western US are at least partly on biological control now. For their operations, it's cheaper & less work than relying on pesticides. But the transition period, when everyone was figuring out how to make the switch, was rough! Growers were used to having a busy spray schedule. Just not spraying at all felt wrong. The plants were getting eaten. You're supposed to apply something when that's happening! At least one crop consultant got an idea. He'd go out in the vineyards & hand-apply predatory mites onto the vines with a paintbrush. "There you go!" he said. "I applied predatory mites. Your vineyard's protected. Just don't spray anything that would kill them." So here's the thing about that, You only need to put predatory mites onto your plants if you're in a greenhouse. And you need to put out thousands. A few per plant with a paintbrush won't do it. But for crops in an open field, predatory mites usually show up on their own. No application necessary. Ok so that's some grape pest management facts. Time for some winemaking. Tannins: they're the compound that makes wines taste "oaky," "grippy," etc. Some of the tannins in wine come from the grapes, some of them come from the barrel they're aged in. Grapes for winemaking tend to have thicker skins than grapes for eating. Thick skins aren't fun to chew through. But winemakers like a nice thick skin, because that's where a lot of the flavor & aroma compounds in wine come from. They're in the skin, not the inside of the grape. Vineyards for wine grapes can be surprisingly, uh, not as lucrative as we might think. Grapes for eating fresh tend to command a higher price. Why? Wine grapes can be ugly! They get mashed up into juice. But table grapes have to be in good enough condition to ship, & for people to still want to buy them when they arrive. So table grapes are higher maintenance to grow. You'll lose more the crop to un-shippability, etc. That's one reason there's so much agritourism in the winery business. Often, there's surprisingly little money in the vineyard itself. Ok raisin time! This is how most of the raisins in the US are made. They just pick the clusters off the vine, lay them on a piece of kraft paper between the rows, and leave them there until they're raisins. That's it that's the whole process. |
If you've ever walked under a tree & thought "Weird, it feels like it's sprinkling" but there's not a cloud in the sky… they're called sharpshooters because their diet is so watery, they're always shooting the extra water out their back end. 😭