We are not familiar with a local disease called "brown spot," and ID apps often leave much to be desired in terms of accuracy, but we find it more likely that this is either a very minor infection that can be ignored, or just abiotic damage. (Abiotic factors are those that are non-living -- so, not caused by a pest or disease.) These sound like recent transplants. Root stress from being moved can be a very common reason for leaf damage called scorch, where leaf edges or tips dry out and brown because they are losing moisture faster than roots can accommodate, since roots need to recover from the move and then re-establish the plant. Even the most careful transplanting effort tends to damage at least some of the finest roots, which might not be readily visible, so the plant needs time to regrow them.

After the saplings were moved, were they monitored for watering needs regularly? Many areas had a stretch of wet weather, but how much rain actually fell and moistened the ground varied region-wide. Feeling the soil next to the roots, about four to six inches deep, is the best way to judge soil moisture. If somewhat dry to the touch at that depth, watering is probably going to benefit the plant. If damp when checked, watering can wait, as over-watering by irrigating when it's not needed may risk stressing and even killing roots. Root stress from any source (under-watering, digging injury, etc.) can lead to foliage symptoms like the scorch mentioned, potentially some chlorosis (leaf yellowing due to nutrient deficiency), and even premature leaf shedding.

If the symptoms pictured are a type of leaf spot infection, they are not going to significantly impact tree health and can be ignored. Fungicides will not cure any existing infection, and their use could risk harm to other organisms (and oaks are very valuable to wildlife), so they should be a last resort. Plus, they don't always work completely to prevent more infections (especially if the pathogen is bacterial and not fungal), and tend to require several repeat applications well into the growing season to maintain a protective barrier on the leaf surfaces.

Was any herbicide (weed killer) used near the trees either before or after their move? Leaf symptoms like yellowing, distortion (puckering, twisting), or shrunken new growth can all arise from certain chemicals used in herbicides, either those that evaporate and drift onto the plant, or which are carried into the root zone by water movement. Some herbicide ingredients are more likely to affect tree and shrub roots than others. In mild exposures, an exposed plant usually recovers. (Damaged leaves cannot heal, but subsequent new growth should look more normal.) In more drastic exposures, recovery does not happen, but that does not appear to be the case here.

For now, no treatment is recommended, and just keep an eye on the trees. Feel free to submit more photos if the symptoms worsen, or if different symptoms appear. Monitor them periodically for watering needs and, if the area is frequented by deer in winter, be sure to protect the trunks before autumn, when male deer rub antler velvet off on young trees, sometimes causing serious or fatal damage to the plant. For the sake of long-term tree health, if you use mulch around their base to discourage weeds and insulate the soil, keep the mulch off of the trunk itself (don't pile it up against the bark) and put it down in a flat layer only about 2-3 inches thick.

Miri

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