PARTICIPIAL PHRASE. Present participles, verbals ending in-ing, and past participles, verbals that end in-ed (for regular verbs) or other forms (for irregular verbs), are combined with complements and modifiers and become part of important phrasal structures.Participial phrases always act as adjectives.ometimes part of the noun phrase is delayed until the end of the sentence so that that portion of the phrase (usually modifying phrases  participial or prepositional) can receive end weight or focus.
Insect borers often attack trees that are weakened or damaged by other causes. In some cases, borers and plant pathogens are associated with the same canker. Leaf drop Leaf drop is generally caused by plant pathogens or environmental problems.
Why do leaves fall from trees in fall--and can they keep hanging on? Researchers say that they have pinpointed chemical signals that cause leaves, flowers, and fruit to fall from plants â and that, if blocked, might allow them to hang on forever. Scientists already knew there were cells in the tissue linking stems and branches that release chemicals that break down plant cells, causing leaves, et al, to fall off.