In a comment, Andra directed me to a Russian translation of The Crystal Ball. Somewhat surprisingly it seems that this is the only translation that has been made. Although my Russian is slight I was able to read through the text (with some help from google translate), and so I am now in a position to self-answer my question.
The Crystal Ball deals with using insects to carry bacteria to produce epidemics for military purposes. The story opens in a research institute being inspected by a general, who is not pleased with the lack of progress. The director of the institute tells him that a French professor, Chardin, has worked out the conditions for bacteria to be carried symbiotically by ants, and that if they could get access to his research it would help them enormously:
familiarity with Chardin's conclusions could be of great
importance to us. Very big. Even the general data that he has
published would allow us to count on 70 ... even 80 percent mortality.
Among children, perhaps even up to 100.
Chardin has vowed not to allow his work to be used for military purposes, so they hatch a plan to send one of their own workers, Dr Weland, to visit him, worm his way into his confidence, and obtain his secrets. Weland at that moment was on vacation in a mountain hotel, and when he is contacted by an operative, the owner of the resort is telling a long, rambling story about two Spaniards making their way to a supernatural area called The Eye of Mazumak. Weland is annoyed at having his holiday interrupted, but consents to carry out the mission.
Chardin lives in an isolated area of France, and so secret operatives burn down the only inn, so that Weland, posing as a tourist, has a plausible reason to knock on Chardin's door and beg for lodging for the night. Things initially seem to go to plan. The two men drink wine together, and Chardin tells Weland a long story of how he went to Africa and found "the city of the termites". In the center of the city was a black termite mound, and inside that was a small glass ball. The ball has the property of attracting all kinds of insects:
Insects followed me: moths, moths, spiders, hymenoptera, anything. Day
and night they followed me like a buzzing cloud. Actually, not behind
me, but behind my luggage, behind the metal box where the ball lay...
when I arrived in France, everything started all over again. But worst
of all are the ants. If I stopped even for an hour, ants would appear.
Redheads, woodworms, blacks, "reapers", big and small, all reached for
this ball, gathered at the box, covered it with a swarming ball,
gnawed, destroyed all obstacles, choked each other, died, emitted acid
to destroy the steel box.
“The house you are in, its location, the precautions I have taken -
all this is because ants are besieging me ...
Chardin takes the ball from his safe and gives it to his visitor, and then reveals that this was a test. He suspected Weland of being a fake, and so told the story so that Weland would reveal his true interest in the ant research. He tells Weland that the glass ball is just a worthless paperweight, and throws his lab notebook into the fire to prevent it falling into the wrong hands. Weland angrily leaves. The final sentence, "A crystal ball gleamed in the moonlight", leaves open the question of whether the story of the crystal ball was a lie, or whether it was in fact the truth.
With regard to what elements of The Crystal Ball were used in Fiasco, the story about the trip to the Eye of Mazumac is reproduced in chapter 2, The Council. Chardin's expedition to obtain the crystal ball is included in chapter 3, The Survivor. This is confirmed by a comment by the (Russian) translator:
Two inserted stories (by Dr. Vanteneda from ch. II [the Eye of
Mazumac story, CDS] and Jacob Chardin from ch. IV) were later used by
Lem in the novel "Fiasco" (1987).
So the reviewer's statement that chapter 1, Birnam Wood, contained these recycled elements, seems to be a mistake.