Dormant spray for juniper?

[LooselyWired]

Can anyone recommend a dormant spray for a juniper? Do most people use them prior to winter as a pest preventative, or only if a mite, scale, etc infestation occurs?

 

[Bnana]

If you need to spray to prevent pests you're doing it wrong. Under good conditions they can easily survive winter.

 

[Wires_Guy_wires]

I also wonder what kind of pests would be active in winter.. With that I mean, sure there are eggs, but they don't hatch until spring, so treating those wouldn't help. Other sap gulpers stop their gulping and go dormant together with the tree making systemics useless. Contact sprays would be effective, but if the pests hide for winter, you're going to have to shower the soil too.

Borers being the exception to this, they hatch in fall and eventually go dormant in winter, but depending on the specied they could very well keep munching.

The dormant sprays I heard about were usually meant to combat fungi. Those spores are spread in spring and fall and germinate after two or three weeks, that's when most treatments are the most effective. Dormant sprays - afaik - are used to kill any spores that germinate in winter time.

 

[Leo in N E Illinois]

Dormant oil is NOT to kill currently active pests. The point of spraying with dormant oil is to kill overwintering (dormant) insect & other pests, kill the eggs and any overwintering larva and adults. The oil excludes air from coated insect & their eggs, suffocates the eggs. Dormant oil also provides a light protective film that blocks certain pathogenic fungi from getting a foot hold on twigs, buds & bark. "Sun Oil" was a North American brand of dormant oil that may still be available, my container is decades old, but still good. Some of the oil sprays are simply a fine vegetable oil, some are a fine mineral oil. Key is light, easily emulsified oil.

Neem oil has active insecticidal and anti-fungal properties, a neem oil application can function very well as a dormant oil. Many have dropped the use of traditional dormant oils in favor of using neem oil.

Similar in purpose, reducing pathogen load overwintering on the trees, is an application of dilute Lime-sulfur to deciduous trees after they go dormant and loose all their leaves. This is not for evergreens, not for broadleaf evergreens nor for evergreen conifers. The dilute lime sulfur kills many of the fungi that plague maples. I don't use lime sulfur of plants that retain foliage, actually I don't do this one at all, but there are others who advocate it. Key is to get a good handle on the proper dilution, too strong and you will harm your trees.

Neem oil, is really a pretty good dormant oil.

Point of the dormant oil is that it kills off the insect eggs, spores of fungi, and kills off bacteria that will all spring to life the minute it warms up in spring. Lessens the pest and pathogen load for spring. Helps one to have a "clean spring". IT is not about killing currently active heavy infestations.

Prophylactic pest control, is a part of a good integrated pest management program.

 

[Brian Van Fleet]

I use dormant oil, and lime-sulfur spray.

 

[Dav4]

Last January, I discovered a very active spider mite infestation of my JBPs... usda zone 7b N GA. At least here, I can't rely on cold temperatures keeping pest activity dormant. I also use a dormant oil, but am likely to continue spraying with my miticides and fungicides further into the "dormant" period.

 

[LooselyWired]

I’ll check into the neem oil. Sounds like that is what I had in mind. I don’t have any pests now, but would like to keep it that way.

 

[Underdog]

I use dormant oil, and lime-sulfur spray.

Could you share your dilution mix Brian?

 

[Brian Van Fleet]

Could you share your dilution mix Brian?

Whatever the label says on the dormant oil, and about 2T per gallon on the LS.

 

[Underdog]

Thanks

 

[Bonsai Nut]

Make sure you read the instructions, treat when you are supposed to, and avoid use on sensitive plants.

For example, depending what you read, some junipers / all junipers are sensitive to horticultural oils. I never used traditional oils on my junipers, but have in the past used neem oil because it has anti-fungal properties. If you are at all concerned, test the application on a single branch first before you nuke an entire tree. I did not have problems with neem oil on junipers... but that doesn't mean you won't.

 

[LooselyWired]

I see there is a concentrate & a pre-mixed spray bottle. I assume the concentrate is preferable because you can more precisely control the dilution?

 

[butlern]

Make sure you read the instructions, treat when you are supposed to, and avoid use on sensitive plants.

For example, depending what you read, some junipers / all junipers are sensitive to horticultural oils. I never used traditional oils on my junipers, but have in the past used neem oil because it has anti-fungal properties. If you are at all concerned, test the application on a single branch first before you nuke an entire tree. I did not have problems with neem oil on junipers... but that doesn't mean you won't.

Related to this, I heard Ryan Neil say (in a session on Phomopsis) never use oil on junipers, especially western junipers (Utah/RMJ), but I never heard the reason.

He says diluted lime sulfur, only. Maybe his explanation is unpacked in some other session, but if the reasons are clear to any of you, please let me know. Maybe "sensitivity" should be reason enough... but what I would like to really know is: what makes them sensitive?

 

[Dav4]

Related to this, I heard Ryan Neil say (in a session on Phomopsis) never use oil on junipers, especially western junipers (Utah/RMJ), but I never heard the reason.

He says diluted lime sulfur, only. Maybe his explanation is unpacked in some other session, but if the reasons are clear to any of you, please let me know. Maybe "sensitivity" should be reason enough... but what I would like to really know is: what makes them sensitive?

I've routinely used dormant oil on my RMJs. It temporarily removes the glaucus portion of the cuticle, which also temporarily changes the color. I'm not sure if it also temporarily reduces the cold hardiness of the foliage and makes them more susceptible to freezing winds in colder climates... obviously not an issue for me.

 

[PA_Penjing]

I have used dormant oil (mineral oil base) on ERC in the past. It changed the color of the foilage until it rained a few times. I did multiple applications and the tree never appeared to suffer but I personally would be a little nervous to use it on a juniper in winter storage that wasn't getting the oil washed away occasionally. I read somewhere, can't remember, that the color change happened because of a lack of exchange if gases. That seems like it could be a problem long term. BUT that article could have been complete heresay.

 

[TimberLakers]

If you need to spray to prevent pests you're doing it wrong. Under good conditions they can easily survive winter.

I've been to the Netherlands in the Winter, and can understand why you don't have bugs. Some people have bugs in the Winter.