I have several roses that seem to always attract aphids, all types, esp., the little black ones that the ants carry and insert between the petals and sometimes scale. it always seems to be the same rose plants that do the attracting, and the one thing some of the roses have in common is that they are light or white. Or maybe I see the dark, little aphids better against the light surface. But I do not think so. Scale seem to be totally colorblind and maybe they are being more opportunistic about attacking (I should say attaching) anything that happens to be in their most direct pathway, again carried by ants. I ahve been working on getting rid of the ants since we first moved in (20 yrs) and while I have made inroads, I do live between about 5 acres of open canyon filled with scrub. I have not grown many white nor light yellow roses, but do get them as seedlings, a few of which are nice. The only market-purchased white rose I have is Moondance, and it does not attract anything other than gophers, but that is a different story. Any great fixes for aphids that are mostly non toxic and friendly to bees? And the scale as well? This past yr the scale started to make a serious inroad.
ladybugs but spray them with a little sugar water so they have a chance to stick around
The sugar water can help, but they’re also usually also thirsty. I water the garden over head first so there is easily accessible water. Then put out some of the sugar water spray if you wish. Lady bugs usually remain stationary in the dark, so about dusk, release some at ground level, the base of the plants. They automatically climb up to the tops before flying. Along that path, they’ll find food and lay eggs. Providing food and water so they make use of it instead of leaving to search for it; releasing them in batches over several days; releasing them low so they have to climb the plants (eating and laying eggs as they go) before flying; and releasing at dusk so they hunker down for the night instead of flying away should help you get more established IN your garden instead of inoculating the rest of the neighborhood.
I do have lady bugs a good portion of the yr., and the tiny bush tits (little birds that seem to live on aphids and scale) probably even do more, but whatever this dark little aphid is called, it hunkers down between the petals where I am pretty sure the ants have deposited it. the Lady bugs and the birds do not even seem to notice that they are there-I am sure that it is a survival mechanism. And when it attacks a rose flower, the rose seems to be host to that particular aphid for the rest of the yr, every flower. From a distance they are not noticeable, but up close they ruin the flower. I have been relying on a balance of nature type of pest control which is working, except for this particular little sucker. And when I pick one of these roses, it is like it explodes with ants. But there are aphids in the deep down center which is easily seen when removing petals. One rose might be host to them and the next ten or more not touched.
Did you try an aspirin spray to boost/trigger the immune system?
http://onlinelibrary.wiley.com/doi/10.1111/j.1570-7458.2006.00503.x/full
I wasn’t thinking immunity and bugs, but that is a possibility. Thanks.
Author: MILES P W
Author Address: WAITE AGRIC. RES. INST., UNIV. ADELAIDE, ADELAIDE, S. AUST.
Title: DYNAMIC ASPECTS OF THE CHEMICAL RELATION BETWEEN THE ROSE APHID MACROSIPHUM-ROSAE AND ROSE BUDS
Published in: Entomologia Experimentalis et Applicata, volumn 37, pages 129-136, (1985).
Abstract: “Dynamic aspects of the chemical relation between the rose aphid [Macrosiphum rosae] and rose buds.In warm weather, M. rosae (L.) walks off buds of hybrid tea roses during a critical period coinciding with the opening of the sepals. This behavior could not be related to histologically detectable barriers to feeding, nor to changes in the water content of the tissues or in their composition with respect to total soluble carbohydrate, amino nitrogen or phenolic compounds; major changes in tissue chemistry, effected by spraying the bushes with urea, did not affect the time at which the aphids left the buds. Tissue sap expressed from stems and sepals showed a significant increase in catechin content after, rather than during, the critical period. Once expressed, however, sap from buds at the critical stage showed a sharp in vitro rise in catechin content over a few hours, up to levels approximating those against which the insects discriminated in choice tests. The insects could well be sensitive to a developing capacity of tissue to accumulated catechin, possibly in response to their feeding activity.”
According to Google Scholar the following papers have cited the above paper.
http://scholar.google.com/scholar?cites=1017735430467485448&as_sdt=2005&sciodt=0,5&hl=en
Maybe some roses are just tastier to them but I also think that they are more noticeable on the paler colors so we see them more quickly. For me I notice that they seem to like the ones that have greener new growth as opposed to the reddish new growth. But then again maybe it’s just because they show up better on that green than the red. In any case I don’t worry much about aphids. I just run my fingers up the buds and wipe them off followed by a good hard water spray and they’re gone. I might have to do that a couple of times to get the new hatches but it works.
This may be a total coincidence but the 3 roses that get this particular aphid, which do not seem to appear on the buds (the birds take care of those) are all light new green growth-not the deep colored red or bronzy green. They inhabit the inter-petal areas which seems to go unnoticed by birds and the lady bugs do not fir. Actually they sometimes go unnoticed until I pull off a few petals and then they are visible around the base of the flower-but the immunity thing is a good point, since they seem to be calling out to the ants to bring on the aphids.