How do I get good growth on my Sago Palms, and avoid pests
I have a 10 year old potted Sago Palm. But since last few years whenever a new growth is about to produce new branches on the plant, it's been attacked by caterpillars and they eat away new tender growth. I tried Ganexine powder to control it but it's useless. Please advise me on any home remedies to ensure its new growth.
One more thing which I would like to add is that my plant is in a pot, medium sized. Should I move it to a larger one or is it ok with a medium size pot?
Are you sure the attackers are caterpillars? If so, they must be either hatching from eggs laid on the plant or in the soil by moths or butterflies, or crawling to your sago from some other location. You can place cardboard or foil around the base of the plant - that helps keep crawlies from getting up. You can sprinkle diatomaceous earth on the soil soil surface and on the ground around the pot; that will also help stop the crawlies. Bt products are always effective against caterpillars: https://www.gardeningknowhow.com/plant-problems/pests/pesticides/using-bacillus-thuringiensis.htm
Also, if you see caterpillars, you can hand-pick them.
However, if you never see the caterpillars, you might have snails or slugs. They feed only at night, and hide during the day down inside your soil, or under the pot. Here's more information about these: https://www.gardeningknowhow.com/plant-problems/pests/insects/kill-garden-slugs.htm
Regarding the pot size, if your sago has been in the same pot for 10 years, or even 3 or 4 years, that could be the root of your problems. Too long in the same pot, and the soil is not healthy, the roots are cramped, and the plant is weakened, allowing it to be easy prey for attackers. (That could be why you didn't have this problem the first few years.) You should be repotting a sago every year or two, as they are naturally quite large plants. (Unless you're growing it as a bonsai, which is another subject entirely.) Regardless of the size of the pot the plant is in, the new pot should be only an inch or two larger - that is, the next size up. Here are some pointers on repotting: https://www.gardeningknowhow.com/houseplants/hpgen/learn-more-about-repotting-houseplants.htm
And some on sago in containers: https://www.gardeningknowhow.com/ornamental/trees/sago-palm/how-to-care-for-sago-palms.htm