By Frank Herbert
What if you could get rid of all the nasty bugs and replace them with "better" bugs? That is the idea behind The Green Brain.
So the Chinese are the first to embrace the idea and are eager to spread the effort to the rest of the world. But what they are not revealing is that their effort to rid China of "bad" bugs and replace them with modified bees has resulted in massive crop failures.
So Brazil has been implementing the Chinese plan and wholesale extermination of insects has been undertaken. But the insects seem to be fighting back. Deep in the jungle, the insects have created a brain, a brain to guide them in their fight to survive against the poison onslaught from the human world.
A group of investigators enter the jungle trying to track reports of giant insects and of organized attacks by insects. But it doesn't go well for them at all. Almost everyone at their camp gets killed when the insects launch an attack against the camp. Three of them manage to get to an amphibious vehicle and land it in a river they hope will get them back closer to civilization. The vehicle was seriously damaged in the insect attack and is nearly defunct. The three people have to cope with the muggy heat, the lack of food, the dangers of the river and continuing attacks by the organized insects. But all the insects want is to bring the people to the green brain so it can try to talk sense to the humans, that their wholesale insect slaughter is endangering all life on the planet.
This book dates from the 1960s. Hopefully we now know that insects are vital to the ecology of the planet and an attempt to exterminate them all is just foolishness. So the whole premise of the book is rather silly. But besides that, most of the story is concerned with the three survivors traveling down the river and that part of the story was boring. So all in all, not a great read.