The ultimate test of forage quality is animal performance. Producing high quality forages is vital to improved animal performance, whether your goal is more pounds of milk, a higher rate of gain, or an improved conception rate.

Forages provide a major percentage of the nutrients for beef and dairy cattle, sheep and goats, horses and ruminant wildlife. If the quality isn’t right, you can’t feed animals enough forage to achieve production goals.

Forage quality is defined as “the extent to which a forage, whether pasture, hay or silage, has the ability to produce the desired animal response.”

While many factors affect forage quality, the stage of maturity at harvest is the single most important consideration. It also is the one over which producers can make the most progress. Protein content, digestibility and acceptability to livestock drops as legumes and grasses move from the vegetative, or leafy, stage to the reproductive, or seed, stage. For instance, grasses may contain more than 30 percent protein at the immature, leafy stage, but drop to less than eight percent protein when they mature.

Because we have considerable variation in quality among the various forage species, choosing plant species is another important factor in producing high-quality forages. Generally, legumes are higher quality than grasses. Cool season grasses usually are more digestible than warm-season grasses. Plant breeders continue to improve forage quality within species, so variation also exists within species among varieties.

In addition to forage quality, producers need to consider animals’ nutritional needs and match the quality to these needs. For example, a high-producing dairy cow needs a higher quality feed than a dry, pregnant beef cow. Palatability, intake, digestibility and nutrient content are among these considerations.

Palatability is a measure of acceptability by animals when offered free choice. In general, high-quality forages are more palatable. Forages must be palatable for animals to consume enough to meet their daily needs. Research has shown that animals tend to eat more of the better quality forages.

Digestibility also improves with forage quality. Animals may digest 80 to 90 percent of immature, leafy grasses but only 50 percent or less of mature material with lots of stems. High quality forages have significant amounts of protein, energy, vitamins and minerals, but are low in undesirable contents such as fiber and lignin.

– Maple Petiole Borers and Leaf Drop

If it isn’t enough that our trees are trying to produce another set of leaves for 2007 but now we see problems associated with petiole borers attacking sugar maple trees. Petiole boring by a small wasp larvae may cause sudden drop of many sugar maple leaves in your neighborhood. We are already seeing evidence of that. Infesting leaf stems usually break at a darkened area near the leaf blade. Usually, infestations are limited to sugar maples and only about 25% or 30% of the leaves fall to the ground.

While spectacular, the leaf drop has little effect on tree health. Buildups of scales or aphids, or drought stress can cause leaf loss but these typically occur later in the year. Leaf drop, due to borers, is seen earlier in the season and the leaf blades may still be green. Leaves from trees stressed by sucking insects or drought usually have turned yellow before they drop.

Splitting the petiole carefully near the leaf blade should reveal the larva or the tunnel.There is one generation each year. Infestations begin as the adults, small wasps about 1/6” long, appear in May and lay their eggs in petioles near the leaf blades. Legless, white grubs with distinct light brown heads hatch from the eggs and tunnel inside the leaf stem for 20 to 30 days. The weakened stem breaks and the leaf floats to the ground.

The borer larvae generally remain in the portion of the stem left on the tree. About 10 days after leaf drop, the rest of the stem falls to the ground. The mature larva, about 1/3” long, leaves the stem through a hole in the side and burrows into the soil. It will change to the pupal stage and remain in the soil until the following spring.

Maple petiole borer infestations are infrequent and unpredictable. Also, they do not appear to harm tree health so insecticidal control IS NOT recommended. It may be possible to reduce future infestations by picking up and destroying infested stems, the short sections without leaves, about 7 to 10 days after the first leaves fall. This sanitation program needs to be continued throughout the leaf drop period and must include all infested trees in the vicinity to be most successful. (I know, this is easier said than done, but will help.)