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POD: First Presents Under The Tree

The maximum likelihood (ML) tree was generated with 1000 bootstrap replications using the Tamura-3-parameter model. The ML tree is inferred from concatenated sequence dataset of four genes (ITS, tef1-α tub2, and rpb2). Bootstrap support values greater than 50% are pointed out at the nodes. Isolates in bold represent isolates in the present study and Botryosphearia dothidea represents the outgroup. The bar indicates the substitutions number per position.

POD: First presents under the tree

One century later, in 1734, Charles Marie de la Condamine went to South America on a trip. There, he found two different trees containing latex: Hevea brasiliensis (Figure 1B) and Castilla elastica [3], but only the first became important as a natural rubber source. The reason why the Hevea tree succeeded over the Castilla tree was the way its latex was transported along the trunk. The Hevea tree has connected latex tubes (Figure 1A) that form a network, whereas the Castilla tree does not form a connected system. Thanks to its connected system, the Hevea tree bleeds latex when a special incision is made in its trunk (Figure 2). Without the latex tube connections, the Castilla tree does not bleed latex, making harvest of rubber more difficult.

Garlic mustard [Alliaria petiolata (Bieb.) Cavara and Grande] is a member of the mustard family (Brassicaceae). It is a biennial, a plant with a two-year life cycle, growing its first year as a seedling and rosette stage plant and flowering the subsequent year. It most often grows in the forest understory or along forest edges but is also able to invade undisturbed forest habitats. It tolerates low light levels and is adapted to take advantage of disturbed habitats such as trails, roadsides and areas where trees have been removed. Garlic mustard has no significant natural enemies in North America, although a diverse community of herbivores feed on it in its native range in Europe. Populations of garlic mustard can spread rapidly. In a study of high quality woodlots, i.e. typically old growth or undisturbed forest habitat in Illinois, garlic mustard advanced an average of about 20 feet per year, expanding as much as 120 feet in one year. When established, garlic mustard becomes a permanent member of the community, often dominating the ground layer habitat over extensive areas.

Sites invaded by garlic mustard tend to have low diversity of plants growing on the forest floor and it is widely believed that garlic mustard infestations displace native plants. Researchers in Ohio experimentally removed garlic mustard from a forest understory and documented subsequent increases in the richness and abundance of annuals and woody perennials including tree seedlings. Garlic mustard out-competes some tree seedlings, including chestnut oak (Quercus prinus), which could affect forest regeneration over time. Several compounds isolated from garlic mustard were shown to depress growth of both grasses and herbs in laboratory experiments. Researchers concluded that release of these compounds from garlic mustard root systems might account for its dominance in forest ecosystems. Others have suggested that such compounds might also disrupt mutually beneficial relationships between plant roots and certain fungi in the soil, known as mycorrhizal associations. Like many of its close relatives, garlic mustard does not establish mycorrhizal associations. These fungi are used by most North American forest ground layer plants and are critical for nutrient and water uptake in many trees.

Chocolate was first discovered when the cacao tree was found over 2,000 years ago, in the rainforests of the Americas. Chocolate can be processed from the seeds found in the pods of the tree. The old cultures of Mexico and Central America are the first known people to have made chocolate by grinding the seeds with other seasonings to make a drink. For more information on the history of chocolate, go to Field Museum. New recipes were created in Spain after the Spanish conquistadors found out about the seeds and carried them home. Chocolate quickly spread in popularity, and has remained a favorite of the entire world through the years. For a time line of chocolate and information see Chocolate History.

This week we found our first incidence of scab in apples. While this was only an isolated find on a few leaves, it is a good reminder to take some time to scout your apple trees and look for any signs of scab. Oriental fruit moth numbers were significantly above threshold again this week. Japanese beetles were also


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