Mr Farmer:

It's ok. I've not had the chance to look at the photos yet anyway.

From what you have described, you are doing everything by the book, so nothing to fear. You are really very well informed and well prepared.

Now that you've mentioned yellow patches and predation holes on the leaves and between leaf veins, then I can tell you that you are not dealing with a sap sucking insect like aphids or leafhoppers. You should be looking at tissue consuming ones, like night flying beetles, potato leaf beetles, or even grasshoppers. To confirm this, you need to observe the bite holes for clearly defined edges, could be slightly serrated. If it is not well defined, and excessively smooth, then it could leaf blight/spot or soft rot. You might like to read the attached document as guidance:

http://www.seedalliance.org/uploads/pdf/SpinachDiseases.pdf

If you have identified that it is none of the above, then it would be insect predation. From the feeding pattern (i.e. between leaf veins, serrated edges), it is likely night flying beetles, Apogonia. Check for blackish-brown frass (insect poop) on the underside of the leaves or surrounding leaves. If you find those, then you are most likely having those feeding on your bayams. Other possible pest could be slugs and snails.

I can't give you a definite answer just yet as I'm away from my computer. This computer I'm using now kind of sucks.

Dimethoate, like I said previously, is actually a contact poison, meaning it kills upon contact with the insect via absorbtion through the insect breathing pores. It can act as a systemic, but that is only because the poison is absorbed by the plant itself, making the plant poisonous. BTW, systemic does not necessarily mean slow; it only defines the mode of delivering the poison. Systemic poisons are meant to be delivered into the "body" or "system" of the targeted organism and kill them from inside. Contact poisons are meant to cause death upon touch or inhalation (by killing lung cells leading to suffocation). Think of systemic poisons as lethal injections, and contact poisons as electric chairs.

Personally, I really wouldn't use dimethoate because of the very high risks involved (it has been known to attack human nervous system, leading to symptoms similar to Parkinson's Disease or stroke). Instead, I would use cypermethrin; although it is also dangerous, the risks are less compared to dimethoate.

Mr Farmer:

Looks like you've got phytophtora root wilt, aka damping off. It has to do with high soil wetness (not just damp, but soaking wet), allowing phytophtora to proliferate. Nothing much can do, except cultural control, i.e. raised beds, drainage etc., and crop rotation. Or, you could try using fungicides like Benlate (active ingredient benomyl) before you do your planting. I wouldn't normally advice doing prophylactic spraying of fungicides, but it does help. Just alternate between benlate, and something else, like Kencozeb or Mancozeb.

You might want to avoid plants from the nightshade family, including eggplants, chilies, tomatoes etc. Legumes should be alright. But keep nightshade family crops out for at least 1 year before attempting to plant again.

Mr Farmer:

Hahaha.... Banana by far is easier. You don't have to harvest banana when it begins to ripen, unless you have a thing against using carbide or ripe apples to speed up ripening of green bunches lar. Only that with hilly land, the yield potential drops quite a lot.

However, isn't the light intensity of rubber inter-rows (even on terraces) very low? Or do you mean something else?

Mr Farmer:

Before you go into Cavendish, please get more information on the crop. As I know, for export purposes, Cavendish need chill room treatment. And fingers ripen at different rates, very uneven. Prices are good though, at about RM5 for 5 fingers in many retail outlets.

Bro, groundnuts need sandier soils. Bris series soils are suitable. You could try planting, no harm trying.

The reason I recommended banana is because it generates more income compared to other crops without the need for much value adding. If you're not too particular, you could try planting legumes, like Azuki or mung beans. They can help in nitrogen fixing, i.e. add nitrogen from air into soil, so it might be a good choice. Returns are not great though, about RM1,635 per acre if yields are around 15 cwt/acre. Some Australian growers I know actually intercrop mung beans or peas with corn, both to add nutrient to the soil, and also as a secondary crop to corn since the beans or peas are climbers.