Question
I just planted four rose bushes in the beginning of June. They were all doing real well until about a week ago. We live in Central New Mexico. The leaves on three of the rose bushes seem to have a kind of sticky substance. The leaves are turning a darker brownish green and the tips are dark brown. I tried to cut out the bad leaves, but it doesn't seem to help. Is there a site I can go to to see pictures to find out what is wrong with these bushes? The leaves seem to get very thick and just break. Some of the leaves are turning yellow.

Answer
There is only one insect that excretes a honey like substance which makes rose leaves sticky and that is aphids. There are quite a few different kinds of aphids so I couldn't say which ones there are. They are sucking on the liquid from the leaves and this makes the leaves slowly die and dry out.
http://www.pmra-arla.gc.ca/english/consum/aphids-e.html
If the leaves are damaged and the tips are brown this could be fertilizer burn. If some fertilizer is on the soil when it is very how, some roses will re-act to it by the leaves drying out. The last thing I can think of it spider mites. These very tiny spiders also such out the liquid from the rose leaves and cause them to discolour and die.If you Google "aphids" you will be able to see pictures of them and their damage. Hope this helps.