Pine Tree Pest, Pine Adelgid insect

White woolly secretion around the base of the needles of Pinus thunbergii indicates the presence of the pine adelgid insect (Pineus pini). This pest is related to aphids which suck the sap from plants. In my nursery both Pinus mugo and Pinus thunbergii have been affected possibly due to the plants being placed too close together and from an uneven watering regimen. I use an oil based spray to remedy it.