Rose Gall - Diplolepis rosae

Watering my garden this morning, I noticed yellowing leaves on my Rosa glauca. A sign of heat stress. Yet, as I looked closer, I saw a mossy mass which I've only ever seen once before.

I knew this is a rose gall, but I wasn't sure what was causing this gall.  Galls can 'grow' on all sorts of plants. Sometimes it's a sign that the plant is stressed.

I took my secateurs and cut the gall off with two sets of leaves at the base of the gall.

Mossy hard mass. Really cool.

Took my secateurs and cut the gall in half. Found several larvae in sections. Each within their own chamber.

They are in fact larvae from a wasp.

Non-native - an European introduction called: Diplolepis rosae.

The most fascinating aspect is: how the heck did they get in there?

Adult wasps lay eggs on the plant and once a larva hatches, it begins to feed on leaf bud tissue, and an amazing process begins. The host plant is stimulated somehow with the feeding, where cells from the surrounding tissue multiply, adding layers of tissue - forming this gall. The larvae within, creates a microhabitat, where not only they are protected and housed, but the chambers they indwell also become their food source.  A hotel with room service, if you will.

Pretty cool.

However, since it's an non-native intruder, I squished the gall and disposed of it. Removing and destroying it may sound harsh, but doing so before the gall dries out and the wasps emerge, will help to reduce the infestation. I fear if we don't handle these invaders properly, they will take over and cause major issues down the road.

Neat eh?

Rust on Roses - Phragmidium tuberculatum

Now that it's November, leaves are dropping everywhere.  Yet, this David Austin Rose  doesn't seem to want to let them go!

Notice anything wrong with the leaves?

Those brown/reddish speckles are not normal.

Turning this set of leaves around, do you see the little orange bumps?

This is called Rose Rust (caused by a parasitic fungus called: Phragmidium tuberculatum). Very common, among numerous rose cultivars, especially older hybrids. Some roses are far more susceptible to it than others.

Given the rose will eventually drop its leaves anyway - I removed every one from the rose and they will go in the garbage. This form of rust persists until the leaves drop and if I don't remove them from the site, the probability is higher for the rust to return next year. The best is to destroy or toss in the bin.

I've seen rust so bad on roses, that large lesions can be seen on the stems as well. Thankfully, in this circumstance, I didn't notice any.

Usually I give the roses a hard cut back in the spring, but in this case, I hit it back hard to promote air circulation over winter and come spring. Poor air circulation is one of the main causes of rust developing.

Rust can weaken the plant, diminishing flower bud development. What's a rose without its bloom?

There are fungicides on the market, but I rather use this preventative method, in hopes it will not return next year.

The black pimples, or pustules are the ones that over winter for next year.  The photo above shows how the orange bumps begin to darken to black. This is why you must remove the leaves.

Leaf removal can be done in the summer too, as many roses will respond by re-foliating.

Well worth the effort.

Red Banded Leaf Hopper - Graphocephala coccinea

It's the beginning of October and as we start to prep for autumn clean up, I noticed our David Austin Rose has set a bunch of new buds and on closer inspection, I noticed these beauties.

Wow. I've seen dozens of leaf hoppers before, but this Red Banded Leaf Hopper (Graphocephala coccinea) is beautiful! I tried taking several cell phone photos, but at this size I couldn't capture their intense colour properly.

Leaf hoppers are sap sucking insects, and as they feed you'll see honeydew droplets excrete from their rear ends. If numbers were greater than the 5-6 that I saw on the rose, I would relocate them. Too many and they would suppress the sap from reaching the buds.

Completely yellow beneath, they can hop quite a distance from plant to plant anyways. I let them drink and do their thing. Incredible colour display, eh?

Nature is so beautiful.

What's eating my rose, this time?

Lack of rain this June has made our roses suffer. Having chosen Rosa glauca for its drought tolerance, the heat these past few weeks has stressed the bush inviting so many pesky insect issues.

Two weeks ago, I dealt with the Rose Plume Moth eating the flower buds and now I see this:

More webbing and another green larvae. This one skeletonized older leaves and punched holes in new leaf growth.

Ah-ha...here's another "caterpillar" that folks know to feed off roses.

This is in fact not a caterpillar, but a Rose-slug Sawfly Larvae (Edelomyia aethiops). So you say: what is the difference and who cares?

There is a BIG difference.

I learned in school: the Sawflies Larvae have enough prolegs to spell S-A-W-F-L-Y (6 or even more). Caterpillars have usually 5 or less. Here is great website page that explains prolegs  and their differences.

Here's the Rose Plume Moth Caterpillar to show you a comparison:

Rose Plume Moth Larvae (Caterpillar)

Rose-slug Sawfly Larvae

Sawflies tend to have rounded heads, with visible eyes.

Knowing the difference helps to ascertain that BTK  as a pest control, will be ineffective against the sawfly larvae.

Hand removal has done the trick in this instance, but I would use neem oil and or oil based pest spray control in early June as a preventative. It coats larvae and any eggs that hatch on the underside of the leaves, where the adults have strategically placed them. One to two applications would do the trick. Thankfully, this European introduction, only produces 1 generation per year.

At least the Koi will enjoy a light snack!

Let's see what else our roses will endure this summer.