Plant Diseases/Potted Meyer Lemon
I live in zone 3, Montana, and we heat with wood heat. Hard to keep humidity in the air. Move plant out in summer. 10yr. old lemon and I have always struggled with bugs. Before it started to produce I used a systemic. Haven't for several years. Having a spider mite problem. Took outside (mild day)yesterday and sprayed it with a Hard water spray. Have been using insecticidal soap, but never seem to get ahead - more often? New growth leaves look sick - need fertilizer? Which one and how much. Just picked a dozen or so fruit and would like to the new fruit coming on. Should I repot? I love this little tree and would hate to lose it. Pics included Thank you so much Georgann Watson
Spider mites can be a real PAIN! Using insecticidal soap and spraying the plants with a strong water stream can help. They are often on the undersurfaces of the leaves, so be sure to direct your water stream there. These teeny weeny critters suck plant juices and can have many life cycles per season. They often are more of a problem during hot/dry conditions. Unfortunately, the two practices that you are using are probably the best under the circumstances. As far as frequency of using the insecticidal soap, just follow the instructions. This stuff is quite safe to use. They are difficult to bring under control if the population is allowed to increase
There is a product called Kelthane that is a very effective miticide IF YOU CAN FIND IT!! If you can find it, make sure it is labelled to use on citrus. Some materials can injure the plant, so be sure it is safe to use on citrus--that is if you can locate some. It has been off the market for some time, but there may be some out there on a shelf in an older garden center.
As far as to repot or not, best to carefully remove the plant from the pot and see how compact the roots are in the container. If they have almost filled the container, best to repot. The roots can become so compact that their function becomes impaired. This will show up as yellowing or even wilt eventually.