I don't think they look bad. Bamboo frequently change out leaves. Bamboo also suffer from few pests. Not sure what that white stuff is, but doubt it's serious. It's very difficult to overwater bamboo if you have good drainage. Bamboo in pots tend to not do as well as plants in the ground because they can get rootbound. How well do the pots drain, and are the plants putting out new leaves? How long have the bamboo been in the pots? How large are the pots?

I'm a little concerned by the appearance of the soil, as it looks sort of gloppy. What is it composed of?

The picture of the white stuff isn't clear enough to determine what it is. Could be harmless fungal mycelium/hyphae or could be root mealybugs, among other options.

It's never a good idea to use a toxic insecticide without knowing the identity of the culprit.

There is a good chance the white stuff is mealy bugs, which is very common with many species of clumpers where I'm at in Florida. As for the health of the plant, bamboo is a grass and I've never had much success with keeping them healthy in pots. If you can, put it in the ground and see if it improves. Aside from that, my advice would be to only water when needed, as most bamboo do not like to have wet feet, and only fertilize every couple months.

Agree to get it in ground w root barrier.

The photo shows the soil as quite wet.

The leaf damage indeed could be caused by too much water*, root disturbance, bug feeding, fungal or bacterial attack, and/or salt/fertlizer burn of root tips. Generally this is easily solved with the right soil mix, pot type/size and watering method.

Roots must be healthy to transport water to leaves so that the leaf edges don't dehydrate and sunburn. Soil has microclimate and microflora to combat fungi and insects. It gives drainage, nutrient snd gas exchange. Adequate air for root health maintenance or recovery is important to plants. Drainage, access to moisture (not standing water) and adequate air axchange is easy to get in average garden soils, unless there is too little organic matter or too much clay.

*Even with light watering, I've seen leaves like this for pots set into shallow saucer or plates, which reduces watering needs. Salts can build up if you don't flush when you water, and with prolonged wet rots can set in, or the soil capillaries can be water filled and too little oxygen might get in.

For potted plants with average water needs generally let the soil dry enough that you have to poke your fingers in 1/2" before you feel much moisture. And water enough so some dripping action us seen out of the drainage holes and salts can flush away.

I do not let pot bottoms stand in even a cm of water, unless it is a bog plant! Constant standing water is only good for bogs plants (but they better flush). Ideally average garden plants in a pot should dry enough to need watering every 3-4 days during the growing season. If not in this range you not are watering right or the pot is not sized right for the pot. In pots soil often packs with time, unless there is enough root action to loosen it. In the ground (the ultimate in large containers) their is worm and insect action to make water drainage air/exchange capillaries.

And if it is dry 1/2" down but wet in the bottom lower section most the time, the potting mix is too old (organics break down) or it is calcium salts filled. Thus, repot it. Clay pots aerate better through the sides and so overwatering used to be less of an issue. We use so many plastic pots now l that correct pot size has become more critical. Modern potting mixes are ammended with more fluffy peat and porus perlite and sand to get better balanced moisture, air, and drainage.