Your twelve-year-old self is probably assuming (or hoping) that nasty web is just the result of some harmless, tiny spider. But, little does she know, that web could be the result of many creepy pests that call vineyards their home...
Webspinning Spider Mites
As the primary pest of the coastal growing areas, web-spinning spider mites are responsible for destroying vitis vinifera leaves. Their process starts out slow with small dead spots appearing on the leaves. Slowly but surely, these dead spots spread and result in a total take over of the plant. Soon after, the whole plant becomes engulfed in spooky, sticky webs. Unfortunately, in order to fully destroy these spider mites and prevent further destruction, biological or chemical efforts must be involved. This turns a once lovely vineyard into a brutal battleground between spiders and predatory mites or chemical treatments.
Scales
Sounds innocent, but they are definitely, definitely not. What we have here is a pest that goes unnoticed because it easily blends in with grapevines. With their tiny, needle-like mouths, scales suck out all of the nutrients vines need to survive. Think of them as little vineyard vampires (but not the sexy kind). The loss of nutrients causes the plants to become so weak that they can no longer grow. Then, since that destruction apparently wasn’t enough, the scales produce honeydew - it’s basically like sticky bug poo. This honeydew attracts ants. First the vine endured an infestation of scales and now it has to deal with the takeover of ants. Somebody call Stephenie Meyer, we have a new script for her.
Glassy-Winged Sharpshooter
Let’s just take a moment to appreciate the scientist/genius wordsmith who came up with that name. These buggers attach themselves to the vine so they don’t lose their balance while feeding on the plant’s luscious leaves. From the leaves, the glassy-winged sharpshooters eat their way down to the vines. Once they get deep into the vines, the sharpshooters go directly for the jugular, a.k.a. water conductors. The conductors are exactly what they sound like; they make sure water is getting to every inch of the vine. Once they are destroyed, vines lose their leaves and begin to dry out. Their death is slow and painful. While the male shooters continue to eat their way around the vines, the females are busy laying 80+ eggs. After laying their eggs, the female sharpshooters are obviously starving, so back to snacking they go. Glassy-winged sharpshooters, they’re just like us.
Angular Leaf Scorch
The Angular Leaf Scorch is a disease that infects and destroys the, you guessed it, leaves of the vines. A grapevine’s leaves support the plant through its constant growth and change. When the leaves are sabotaged by a stupid fungus like Angular Leaf Scorch, it makes it very difficult for the vine to get the nutrients it needs to produce grapes. A lack of grapes means a lack of wine, which is, of course, the scariest nightmare of all. The Scorch starts deep within the leaves’ veins. As it continues to spread, the coloring of the leaves change from yellow to red, or even brown. Sure, it’s fall and we love the ever-changing color of leaves, but this is not what you want to see on a grapevine. One session of infection is usually it for this disease but if it’s a wet season, the scorcher will come back to haunt the vineyard for round two. Despite the rad names, these insects and diseases have the power to cause great damage to a vineyard. Chemicals are often involved in the debugging process, which is equally scary. The next time you find yourself wandering through a vineyard, be sure to keep an eye out for these pesky pests. But beware, where there are bugs there is, perhaps, the scariest nightmare of all...no wine.
Sources:
http://wine.wsu.edu/extension/grapes-vineyards/grape-pests/ http://ipm.ucanr.edu/PMG/r302400111.html
http://ipm.ucanr.edu/PMG/PESTNOTES/pn7408.html
https://ecommons.cornell.edu/bitstream/handle/1813/43069/angular-lf-scorch-FS-NYSIPM.pdf?sequence=1&isAllowed=y
http://entnemdept.ufl.edu/creatures/fruit/glassywinged_sharpshooter.htm
