I've dealt with scale on some ornamentals before, but not psyllids. They are somewhat related, I believe. I used neem oil at the time.

See link to an article on this below. Suggest you read entire article.

Salient points:
"Many gardeners prefer to use organic products. Ultra fine oil (Safer Sun Spray and similar products) provide relatively good control of the psyllid in greenhouse studies, according to Trumble, but insecticidal soap is not as effective. Sprays containing an extract of neem oil (Greenlight Neem Concentrate) help control a variety of garden pests and may also work on tomato psyllid."

here's another important point:
"Broad sprectrum insecticides such as malathion will kill tomato psyllids, but frequent use also harms beneficial insects and this may allow other pests like spider mites and leaf miners to build up. The insecticide carbaryl (Sevin) should not be used to control psyllids because it can cause the pest population to increase."

Here is a link that might be useful: psyllid treatment and prevention