The two articles included here are from separate experiments. The first concerns the influence of walnut aphids on production and quality of Payne walnuts, on trees whitewashed in the normal practice for prevention of sunburn. This trial showed a marked loss of both production and quality resulting from aphid infestations. In the second trial, the walnuts were not whitewashed and were subjected to varying degrees of aphid infestation. The resulting evidence showed that most of the sunburn problem was aphid-related. If aphids were controlled, sunburn was reduced to a non-economic level. In orchards where codling moth was not a problem, a recently introduced parasite provided adequate aphid control.