Lots of Bud Drop

[tropicalken]

I am experiencing a lot of bud drop on very young buds. I know this is a sign of the gall midge, but I was wondering if it might be a reaction to the severe heat wave we had last week? I have had a great deal of the yellowing and dropping of leaves because of it. Will heat waves cause bud drop that looks similar to an infestation of gall midge? I'm not wild about using chemical controls on the plants if I don't have to.

[Ernest]

Ken, are you in southern California? I'm in Orange County and I had a ton of yellow leaves with the heat wave--more than I have ever had before. I haven't noticed any increase in bud drop during this time but I have seen evidence of thrips infestation and I think the heat may have been a stimulus to that. Thrips seem to be the main cause of bud drop in my outdoor plants. So far spraying with Spinosad has been pretty effective in getting rid of these pests.

Erny

[Jonathan]

same here. I assumed it was because of the heat, but now I wonder.

[tropicalken]

Ken, are you in southern California? I'm in Orange County and I had a ton of yellow leaves with the heat wave.

Thanks for the advise Ernie. I didn't lose older buds, just very young ones. Do thrips also attack the young buds. The yellowing of the leaves was the worst I've ever seen also.

I live in South Pasadena, about 20 minutes east of Darren, but I'm not a big forum poster. I have built up quite a few new hibiscus plants from Charles and finally know how to make them bloom. I'm seeing bloom on some of my old cultivars from the 80s that hardly ever bloomed before. I never fertilized enough before. My favorite oldie is Herm Geller. It seems to be in heavy bloom all the time.

Many years ago I ran a Hibiscus club but eventually got tired of doing the work involved. That was before all the new hybrids were so readily available. I used to have to travel to Florida to find hybrids.
Another fellow nearby and I have talked to Darren about possibly starting up another hibiscus group in the Southern California area. We want to meet up sometime in June or July after Darren gets back from Hawaii. Does this have any interest for you? Do you know others in the area who are into hibiscus that might be interested?Let me know your feelings on this.

Ken

[farmer d]

I have also had ridiculous amounts of yellow leaves from the past two heat waves with the one last week really wreaking havoc on my plants.  I would say I have lost 1/3 of the leaves on my plants.  The ones getting the hot afternoon sun lost the most. 

What really helped was Erny checking his for spider mites.  I think it is safe to say this was due to the heat and terribly low humidity.  Last Thursday it was 103F here with 7% humidity.  Brutal and it is only May!

Farmer D

[Ernest]

Ken, I don't know exactly when the thrips get into the buds but I presume it is fairly early in the cycle. I can tell when I have them because certain cvs show a lot of "scratching" on the flowers. Usually after two sprayings with Spinosad about a week apart they are gone but I have to wait for a new cycle of buds for the visible scratches to go away.
I had to laugh when I read how you hadn't fertilized enough on your old cvs. I too had some oldies from Florida that hardly ever bloomed but I wasn't giving them any fertilizer at all! I called the guy in Florida who had shipped me the plants and of course the first thing he asked was how often I fertilized. Somewhat embarrassing to admit how stupid I had been. I had a lot of old ones growing in the ground for 10-15 years so they had reached fairly impressive sizes. But I took a lot of them out in order to make room for the new ones from HVH. Herm Geller was also one of my favorites and I do miss it.

Erny

[Charlie]

Most of the time, bud drop is thrips related. If the buds are large, and then turn a kind of rotten yellow and fall off, thrips are most likely. However, if the small buds turn bright yellow and then fall off there is a chance that you imported some gall midge from Florida. The hibiscus gall midge does not naturally live in California but can arrive inside buds of plants sent from Florida. If that happens a fast response is needed to get them under control before they become established in your neighborhood. That can become a bigger problem since they spread back and forth between neighbors since it is unlikely to get an entire neighborhood to treat for them at the same time. Fortunately, colder areas of California are not good environments for the midge to last through the winter but some of our coastal areas might be.

Charlie

[Gil]

I have sprayed Spinosad 5 weeks in a row, but can't stop the bud drop or Thrips damage on 50 new CV's. Many, I'm still waiting on it's first bloom, but all the buds drop. I'm getting about 80% dropping, 20% blooming distorted with scratches. Certain CV's seem to be more resistant to Thrips, as they keep blooming, even being in the same pot with other infected plants. (Antique Treasure and Chocolate Berry Truffle, Purple Magic)

My 30 CV's from last year are all experiencing root rot, so I have my hands full. Now that I removed the trays from beneath the pots, they seem to be doing better, but lost 90% of leaves. There is a lot of new growth and will take this opportunity to trim them back.

[Kyle]

for me,  yellow leaves is usualy a sign that I may be overwatering or watering with water that is to high in alkalinity.       If I cut back on watering by letting the soil dry more before watering again my plants do better hence dry feet.    The weather has been very inconsistent.  90 and humid for 2 days then back down into the 50's overnight with lots of rain.  To much rain tends to bring out the yellow leaves for me and a sudden raise or drop in temp will cause the occasional bud drop for me to.   

[farmer d]

My experience has been that you can get a lot of bud drop with overwatering and/or lack of correct fertilizer mix.  When I got back from being gone for three weeks my fertilizer had run out in my drip system so my plants were getting only water every other day. 

I saw all the tiny baby buds falling off everywhere along with some branch tip die back.  The thrips markings on my blooms has just about all cleared up so I don't see them as an issue at this point for me so it is the amount of water and ferts causing the bud drop.

It is super important to remember what you are seeing now was caused by conditions three weeks ago on average.  Don't over react, give your plants a chance to show you if what your are doing is going in the right or wrong direction.

Gil, be careful about making your pests you have immune to what you are spraying.  You have to mix it up every couple of weeks to keep them off balance.  I suspect most of your problems are just from too much rain and the lack of drainage.  Give it a month and you should see your plants start to recover. 

I find exotic hibiscus to be momentum plants so hopefully they rebound quicker as time goes by.  I know it is hard but be patient and super observant.

Farmer D

[Charlie]

Gil, if you are still experiencing bud drop after treating with spinosad it is either because the thrips in your yard have become resistant to spinosad or it is due to hibiscus midge instead of thrips. This midge is a scourge of Florida hibiscus, so it is worth figuring out the problem.

Spinosad will stop working after about 10 sprayings or a solid year of using only spinosad for the thrips. It is necessary to spray an alternative thrip killer for awhile and then the spinosad will work again. Orthene (or any pesticide with acephate as the active ingredient) will work, as will the miticides Avid and Pylon. Avid is cheap now that it is out of patent (and is also a great miticide) while Pylon is ridiculously expensive and only suitable for wealthy collectors or commercial growers. Acephate is very inexpensive but has the drawbacks of being quite smelly and being a wide spectrum pesticide that eliminates many beneficial insects. For that reason it is best to spray it only over the tops of the plants and the buds instead of trying coat both sides of every leaf the way most pesticides should be sprayed.

Try googling "hibiscus gall midge" to read up on ways to detect and treat gall midge bud drop. This in only a problem in Florida and some other parts of the Gulf Coast. Nobody else needs to worry about it.

Best.

Charlie