My pecan trees are covered with worms and squirrels are eating the pecans. What can I do?
I am uncertain of the pest that is attacking your pecans, but most worms can typically be killed either by using Bt or neem oil. Here is more information: https://www.gardeningknowhow.com/plant-problems/pests/using-bacillus-thuringiensis.htm
https://www.gardeningknowhow.com/plant-problems/pests/pesticides/neem-oil-uses.htm
This article will help with the squirrels: https://www.gardeningknowhow.com/plant-problems/pests/animals/get-rid-squirrels.htm
Large limbs breaking off.
Hopefully you can find an answer in these articles: http://www.wildflower.org/expert/show.php?id=8648
http://www.plantanswers.com/pecan_limbs.htm
https://www.gardeningknowhow.com/edible/nut-trees/pecan/pruning-a-pecan-tree.htm
When is the best time of year to graft pecan trees? I cut the stock to be grafted in the winter and it has been stored in the refrigerator. Now I just need to know the best time to graft.
Most grafting can be done in early spring but is really dependent on the type of grafting you are doing. This resource may help: http://www.extension.umn.edu/garden/yard-garden/fruit/grafting-and-budding-fruit-trees/
I have one big pecan tree that I think is full of sawflies. How do I get rid of them?
This article has information you are looking for: https://www.gardeningknowhow.com/plant-problems/pests/insects/sawfly-insect-control.htm
Also, you should probably identify the problem for sure before you attempt to treat for it. If you can capture some of the insects or their "caterpillars," take them to a nearby Extension Service for help; This link will help you locate the closest one: https://www.gardeningknowhow.com/extension-search/
The squirrels are doing lots of damage to our Pecan trees. We live in town. Is there a poison or anything we can use to eliminate a few hundred?
This article should offer some help with that: https://www.gardeningknowhow.com/plant-problems/pests/animals/get-rid-squirrels.htm
I have 2 pecan trees in my yard and the sap is so bad it kills my other plants. What can I do?
Sap does not generally drip out of healthy trees. Your problem is most likely an aphid or scale infestation, and the sap is the honeydew substance the insects secrete. You will have to spray the trees to get rid of the bugs. This article will give you more information: https://www.gardeningknowhow.com/garden-how-to/info/what-is-honeydew.htm
You can also take some samples of the tree limbs to the county extension service to get their analysis. This link will help you locate one: https://www.gardeningknowhow.com/garden-how-to/info/what-is-extension-service.htm
We're raising the yard elevation around these trees by about 18 inches. Would a well around the trees be necessary? Trees are approx. 15-18 feet tall.
I do think it would be very beneficial to contact a certified Arborist with this question. Bringing the soil up that distance on a tree trunk could be very detrimental and invite disease and insects. A well around the tree could cause water to stand around the base of the tree.
https://www.gardeningknowhow.com/edible/nut-trees/pecan/growing-pecan-trees.htm