Fungal anthracnose attacks these young grapevine leaves.
Prevent This Fungal Disease in Your Garden
How to Identify Anthracnose
- On leaves, anthracnose generally appears first as small, irregular yellow or brown spots. These spots darken as they age and may also expand, covering the leaves.
- On vegetables, it can affect any part of the plant.
- On fruits, it produces small, dark, sunken spots, which may spread. In moist weather, pinkish spore masses form in the center of these spots. Eventually, the fruits will rot.
- On trees, it can kill the tips of young twigs. It also attacks the young leaves, which develop brown spots and patches. It can also cause defoliation of the tree.
Photo Credit: Rutgers University.
Catherine Boeckmann
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This was a great source of information for my school project! Thanks
Anthracnose can be a problem in semi-arid climates (and probably arid ones), too. It mostly seems to be a foliar issue (and a fruit storage problem, too), however. The foliage problem seems kind of mysterious due to the dry air until you realize that anthracnose appears to be what often causes fallen apples to rot after they get too old to eat (apples fall a lot when it's dry), and spider mites (which love dry areas), love infesting apple trees. They are probably all over the rotting apples on the ground, too. I hypothesize that they afterward go on to other things like watermelon to spread anthracnose to at least the foliage of the watermelon. I've found that showering the watermelon plants and such tends to keep the spider mites (and foliar anthracnose) at bay the first half of the season or so (and the showering helps the plants grow faster). So, yeah, pick up your apples that fall (don't let them rot).
The combination of spider mites an anthracnose in my semi-arid area seems to tend to cause speckling of the leaves at first (they look stonewashed); you don't see large or dark cirlces, usually. It can cause the same thing on watermelon rinds, too, without rotting the fruits (the stonewashed look). Anthracnose-resistant watermelons still get the foliar anthracnose just as bad as regular watermelons in my experience (but the fruits don't seem to get the stonewashed look). For breeding foliar resistance, I recommend saving your seeds from exposed plants every year to help acclimatize them to the pests/diseases (if they occur every year). However, I zap my seeds with three frequencies of a Z4EX to hopefully remove any anthracnose pathogens (because if the infection is still there at germination time, you might not see a benefit to saving seeds, and it may spread the disease to other plants). The results of my saving and zapping seeds seem to be positive, so far (especially with my Ledmon watermelons), but more years of doing this are needed.
It should be noted that the combination of foliar anthracnose and spider mites can stunt and/or kill plants. Watermelons that get the problem usually die after a while (Red-seeded Citron is probably the most resistant variety I've grown). Muskmelons seem more resistant than watermelons (on a foliar level).
Do any of you use any nematode to battle bugs?
Beneficial nematodes, commonly species of Steinernema and Heterorhabditis, have been used to control various insects. For example, certain species of Heterorhabditis are used to control Japanese beetle grubs in lawns. For more information, you might be interested in:
http://www.almanac.com/content/lawn-problems-and-cures
If interested in using beneficial nematodes, you’ll need to do a little research to be sure that you select the right species for the right pest, and apply them correctly, for best effect. Good luck!
I have about 3 very large Laurel Oaks in my back yard. One oak has developed leaf die off, and now ha black tar spots on it. Recently noticed possible insect activity at base of trunk, like saw day. Very worried it's dead, and may spread to other Laurel Oaks. Any ideas?
Hi, Dana: The good news is that you have two healthy trees. The other news is that it is difficult to tell exactly what the problem is with the third, despite your valiant attempt at description. It would seem that this is some sort of fungal infection, either of the tree (and laurel oaks have notoriously thin bark) or roots, possibly resulting in anthracnose. The saw dust could literally be saw dust from a nonrelated insect infestation in dead wood, or it could be spores of some sort. The first option in such cases is usually to clean up both the tree (prune) and site as much as possible and keep it that way. If we were you, though, we would not waste any time in calling in a professional arborist for advice. Thanks for asking, and good luck!
I think you mean you wouldn't waste any time before calling in a professional, which means to call one soon, rathern than you wouldn't waste any time in calling in a professional, which means don't call one as it would be a waste of time.
Hi, Ellen: You are absolutely correct: 鈥渂efore鈥 calling in a professional. Thanks for the correction!
it is great to share with information about plant pathology
I have white flies again. I turned on those undercounter lites up bright 24/7 and my house plants were growing so good until bingo,clay pots have that white stuff on them. What im concerned about is the white balls in soil and when i look at roots they have a sm. version that are grainey like . Do these hurt anything ? It seems to be sucking the roots more than leaves. There is also a lite brown coating that covrrs the stems . last time i us a general pesticide w/ o success. Then months later used a sour milk ,butter milk& flour mixture .That did the trick.I have moved since then but i think i brought them in from outside. Saw a few sm bug like flies in a plant i started from bulbs. Im worried about the soil. Has anyone else noticed this ???.Maybe i have a different bug ? I've had plants for 30+ yrs & only ever had was mealy bugs (that cotton stuff when i lived in Houston Tx. Very humid there . If anyone has an answer please help me. I have physical disability
.This is really exhausting. I love my plants !!TY
