Sevin Concentrate is not labeled for hornets or other stinging insects so would not be recommended. It is not systemic and would not be carried back to any nest, either. A better option would be to use a product like Bifen IT on the bushes to help control those that contact a treated area. We also have a great guide on treating waps and hornets here.
It is possible that the bottle of Sevin Concentrate you have could be old. If you shake the bottle and the contents do not mix, this is a good indication that you have old product. If the product was allowed to freeze or if is over 5 years old, we recommend that you purchase fresh product.
Yes, Sevin Concentrate will treat saddleback caterpillars. You would mix 4 oz per gallon of water and apply with a hand pump or hose-end sprayer.
Sevin Concentrate is not labeled to be used on trees with a height of 10 feet or more. Adonis 2F Insecticide/Termiticide which conains Imidacloprid would be a better product to use. You would use .1 to .2 oz per inch of trunk diameter. It can take up to 8 weeks for the product to completely translocate through the tree so timing is key. Application timing of systemics is very important and it varies from region to region. We recommend you contact your local cooperative extension office and speak to the master gardener on staff as he or she will be able to give you the most accurate information in regards to application timing.
For foliar sprays now Talstar P would be a good product to use.
Sevin Concentrate is only labeled for use on fruit trees, ornamentals, vegetable gardens, shrubs, and around flowers. It is possible that it will harm your lawn if used on your turf grass. For future applications, be sure to apply only to the listed areas.
Sevin Concentrate applications are best done before temps reach the daytime high, so you can apply in direct sun just do so in the morning before it gets too hot.
Bayer Advanced All In One Rose and Flower Care treats for many types of pests. Is there a pest that it is not labeled for? We see no reason to apply both. We would not recommend applying both to Roses at the same time.
Sevin Concentrate is best applied when rain is not expected within 24 hours after application. If it rained sooner than 24 hours after application, for apples, the product label states the product can be reapplied no more than once every 7 days and not within 14 days of harvest.