Surprisingly, the answer is no. The State does not have to test the drugs. Officers can testify based on their training and experience that what they seized was a drug, and the jury can believe them.
But without a lab test, things will probably be rough for the officer at trial. For example, I've had officers testify that they knew what they seized was marijuana from their knowledge and experience. However, most officers do not have any specialized training about drugs beyond what is taught at the Academy. The leaves many areas open for cross-examination.
For example, in a recent case I asked the officer if he was properly trained in the Fast Blue Regent, Duqoise Levine, and Hairy Systolic Fibers field tests, why those tests are important, and why he didn't do them. The officer didn't know what those were and he looked like he didn't know what he was doing.
I also asked about the technical definition of marijuana. In Georgia, marijuana has a very specific definition:
all parts of the plant of the genus Cannabis, whether growing or not, the seeds thereof, the resin extracted from any part of such plant, and every compound, manufacture, salt, derivative, mixture, or preparation of such plant, its seeds, or resin; but shall not include samples as described in subparagraph (P) of paragraph (3) of Code Section 16-13-25 and shall not include the completely defoliated mature stalks of such plant, fiber produced from such stalks, oil, or cake, or the completely sterilized samples of seeds of the plant which are incapable of germination.
O.C.G.A. Section 16-13-21(16). As you can see, you can possess parts of a marijuana plant but not possess the controlled substance marijuana.
Another part of the law further narrows the definition of marijuana:
(3) Any material, compound, mixture, or preparation which contains any quantity of the following hallucinogenic substances, their salts, isomers (whether optical, position, or geometrics), and salts of isomers, unless specifically excepted, whenever the existence of these salts, isomers, and salts of isomers is possible within the specific chemical designation: ... (P) Tetrahydrocannabinols which shall include, but are not limited to: (i) All synthetic or naturally produced samples containing more than 15 percent by weight of tetrahydrocannabinols; and (ii) All synthetic or naturally produced tetrahydrocannabinol samples which do not contain plant material exhibiting the external morphological features of the plant cannabis.
O.C.G.A. Sectoin 16-13-25(3)(P). This section makes it much more difficult for the officer--you can possess what looks, smells, and feels like marijuana, but if more than 15% of its weight is tetrahydrocannabinols, then it is not marijuana. Obviously, you can't determine that without testing a sample at a lab.