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I live in Carmel Valley, San Diego and I have a rosemary plant that has been sitting in my back yard for almost 6 years. The weather has not changed for quite a long time. The soil is a free draining sandy soil. A week ago, the rosemary started flowering. It had only flowered once before four years ago. When I looked closer at the leaves, I found yellow spots on most of them:

Yellow spots on rosemary leaves

The camera makes the color more green but really the whole leaf looks yellower and not healthy. Normally I would wait a few weeks just to see if it would go away, but I also started noticing white fruit-fly sized flying insects around the rosemary. I'm also particularly worried because my parsley had been infested by these insects a few days ago:

white bugs on parsley

Also this insect:

Yellow insects on parsley

I uprooted the parsley and disposed of it properly and I'm wondering if these are the same insects that are damaging my rosemary. What do you think is the cause of the yellow spots on the rosemary? Should I get rid of those insects and how?

Some more images: 1, 2

Sorry for the blurry images and thanks for any help.

jkd
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2 Answers2

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Yup, you've got aphids, spider mite...whatever. Is this the first time you've had problems? Go get some NEEM. A great sprayer...or a pump sprayer. Read the directions and cautions FIVE TIMES. Seriously, this is what they taught us in pesticide licensing!! Do NOT do this during the day. This stuff will help tremendously and like now. Make sure you spray UNDER the leaves, very important. Spray the top of the soil lightly. You will have to do this again in another week and keep watch...forever.

Why this began after 6 years would be nice to figure out. What has changed recently...6 months or so ago? Take some pictures of the entire environment...are these in the ground or are they in pots? What have you done within this time? Any changes at all? Is this on the North side of your home?? These insects are very normal but something has changed. Are you using automated irrigation? Did you get a plant from a friend recently? Did you bring in new soil...garden soil from a neighbor? Wear gloves and long sleeved shirts. This stuff ain't that toxic but sure is stinky and some skin doesn't like it. This is as powerful as I will go, just please read the directions and information sheets that come with closely and at least a few times, Okay?

When you want to use the rosemary, just dilute hydrogen peroxide 3% 1 cup in one gallon and swish the rosemary allow to soak for 5 minutes. That will get the Neem off as well as the insect poop and insects dead or alive and you'll be able to use your Rosemary. What are you doing for fertilization? Too much nitrogen and shade will hamper any flowering...

stormy
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  • This is on the south side of my house and the plant is in the ground. We planted some tomato and lettuce seeds in raised beds about a month ago. The raised beds had some Miracle gro garden soil we bought at Home Depot. There is automatic irrigation once a week, but I water by hand every other day. It rains like five times a year here normally, and it rained ten times times last month, so my earlier statement of normal weather is incorrect. Also lots of fog, which is normal. I don't fertilize. – jkd Mar 22 '17 at 02:48
  • The rosemary doubled in size over the last year if that is relevant. Also, does Neem hurt ladybugs? There's been a lot of ladybugs lately and I've heard they are beneficial. – jkd Mar 22 '17 at 02:54
  • Aphids, if you ask me. At least on the parsley. Plus something feeding off the aphids, see the empty hulls - likely the ladybugs and theur larvae. And the specks on the rosemary indicate something biting into the plant. There is one strand of webbing visible, which would mean spider mites, but could also be a coincidence. – Stephie Mar 22 '17 at 07:15
  • Otoh, if it's been wet, that would mean aphids, spider mites prefer and prosper in dry weather. – Stephie Mar 22 '17 at 07:17
  • Let those lady bugs do their thing! They gobble these guys up. Hold off on the neem for now! You WILL be fertilizing when we get done with you, ha ha!! Remember everything EVERYTHING is chemicals even us and all life. Us humans disturb ecosystems where all these necessary chemicals are stripped away so WE have to replace these chemicals so that plants are able to make their own food. Stephie is right, dry weather usually promotes spider mite (need better pictures on the underside of leave to diagnose) and aphids. But sounds like you've got the best control happening. Do NOT NEEM now. – stormy Mar 22 '17 at 16:33
  • One more thing I read that you need to STOP doing is watering by hand every other day. Make your plants WORK to get the moisture out of the ground. High humidity and shallow watering can really promote fungus and insect. Watering deeply once per week is GREAT. Causes your plants to grow DEEP root systems watering shallowly stops them from growing deep roots and as soon as drought sets in they will be affected. – stormy Mar 22 '17 at 16:37
  • When was the last time you pruned your rosemary? Send a picture or two more of the rosemary...one beneath the leaves, please! – stormy Mar 22 '17 at 16:39
  • Agreed, aphids. I mix up about a gallon of water and a 1/4 cup or so of liquid dish soap and spray the plants. You can rinse it off in a week or so and re-apply if you see more aphids. The soap won't hurt the plant and a good rinsing will let you still enjoy the rosemary. – Linda MacPhee-Cobb Mar 24 '17 at 02:20
  • @stormy I don't prune my rosemary. [Here's some closeups of the rosemary leaves.](http://imgur.com/a/aZyDb) Sorry it's blurry, I don't have a good camera. It's getting better, presumably because of the ladybugs. – jkd Mar 24 '17 at 03:52
  • Let the Lady Bugs do their thing. Later in the year your rosemary could use a pruning. Are ALL the leaves the same? You are very lucky to have the Lady Bugs, they are voracious. When they go away let us know...ok? Sure looks like some kind of sucking bug like spider mite. Do you have a magnifying glass? – stormy Mar 25 '17 at 02:09
  • @stormy Most of the leaves are turning greener now. I have a weak magnifying glass, but I took a few test shots with my camera and it didn't make the picture bigger at all. – jkd Mar 25 '17 at 03:08
  • The picture of your Rosemary...there is a 'web', hard to see but there. Spider mite doesn't go away. Allow the Lady Bugs to do their thing, Look beneath the leaves again with magnifying glass and if you see moving specks, usually orangish, write another question to deal with that problem. Glad to hear the leaves are getting greener – stormy Mar 25 '17 at 04:37
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https://gardening.yardener.com/Problems-Of-Rosemary

Botrytis blight... looks like what’s going with my old rosemary but mine are in pots.

Iceproof
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