I have 15 small roses from cutting (less than 2 months) in 1Ga pots (indoor). I found spider mites from when I was propagating them. I applied "Safer's Rose & Flower Insecticide" a few times, but it didn't completely kill the spider mites; they will show up a few weeks later again. And it seems that some of the plants are not strong enough to take the insecticide (a few died, foliage dry out or changing to darker color). I am just wondering if there's anyone who knows what could help on the spider mites problem for young roses. A safe and effective way? Thanks Eric
If it is spider mites ,check with a magnifing glass and you will see them crawling around. Spider mites do not like a moist enviroment so maybe a misting system might help you.
since spider mites are not insects, but rather arthropods with 8 legs, they are more closely related to spiders. An insecticide will not be effective on spider mites. Instead you would need to use a "miticide" , not easily obtained anywhere around here except commercially at a very high price. But, that cetainly is not required on small plants or cuttings. As Greg has already stated, spider mites hate water or moisture and so if you give the cuttings a humid environment, or just wash the leaves everyday a few times that will surely get rid of them. Have the cutting rooted already? It sounds to me that you are taking hardwood cuttings which usually take much longer to root than softwood cutting. At least that's been my experience with roses. I take softwood cuttings during the summer months when the vigorous growing varieties will usually root in about 6 weeks or so. I start these cuttings in pots, covering with a plastic bag to keep the environment moist until rooting takes place. In fall when I'm cutting the roses back a little, I stick the hardwood cuttings into the soil and they stay there until next spring or even beyond as they take much longer to root during fall, winter and early spring. There are however, many ways to take cuttings and what works for one may not for others. Good luck with your babies!
Thanks for the comments. I started my softwood cuttings from Sept. and put them in a hand made acrylic fish tank with a 6400k light. The media I used was Perlite and Peat Moss(3:1) and the temperature was between 70~75F. I open the cover for 20mins twice a day. All of them are rooted with new leaves, and have been transplanted to the nursery pots. The moisture was over 96 while they were in the tank, but the spider mites survived. I'll try to wash them and see if they go away. Thanks Eric
Yup, raise the humididty and consider a miticide. Safers has a product that uses resmethrin with soap rather than just the soap. If you have a greenhouse you may consider releasing a predator insect.
Spider mites are quite easily controlled with a horticultural oil such as UltraFine or Volk. Although it seems to be difficult in Canada to find anything that actually works, horticultural oils should be readily available at most nurseries, and garden centers, as they are 100 percent non toxic, and entirely safe to use. - Millet (1,146-)
