Translated by: Dania Rivera, Ornamental Horticulture Extension Specialist, University of Puerto Rico “El mejor momento para sembrar un árbol es veinte años atrás. El segundo mejor momento es ahora” Anónimo Si vas a hacer algo, hazlo correctamente la primera vez. Esto es cierto para muchos aspectos de la vida, pero, cuando se refiere a la siembra de plantas, esto suena especialmente cierto. ¿Cuánto tú crees que es la expectativa de vida promedio de un árbol en una localización urbana: 40, 50, 60 años? ¿Qué tal diez años? La expectativa de vida promedio de un árbol urbano se estima desde siete (Moll, 1989) hasta no más de 20 años (Roman y Scatena, 2011). Lo que complica el problema es que un árbol maximiza sus beneficios ambientales solo después de los 30 años (USDA-FS). Cuando nos gusta hablar de todos los beneficios ambientales que un árbol agrega a una comunidad, uno debe[Read More…]
Archives for April 2018
Biology: Henbit (Lamium amplexicaule) is a common winter annual broadleaf weed found throughout the United States. It can often be mistaken for another closely related winter annual broadleaf, purple deadnettle. Both can be observed by their showy pink to purple flowers which are primarily produced in April, but can appear from March to November in Indiana. Identification: Henbit is a winter annual, meaning that it germinates in the fall, survives the winter as a vegetative plant which eventually flowers, develops seed, and dies as temperatures increase in late spring to early summer. As a member of the mint family, henbit has a characteristic four-sided (square) stem which can be sparsely hairy and greenish to purplish in color. All henbit leaves are hairy. Upper leaves are deeply lobed and encircle the main stem at the base (no leaf stem). In contrast, purple deadnettle leaves are more triangular, less deeply lobed, and[Read More…]
Three different rust fungi cause gall-like protrusions on eastern red cedar (Juniperus virginiana) trees. The bright orange gelatinous galls with tendril-like protrusions (Fig 1) resembling ‘koosh balls’ are caused by Gymnosporangium juniperi-virginianae. This fungal disease is known as Cedar Apple Rust. The galls develop on the cedar tree (Fig 2) and ‘sprout’ fungal spore-bearing tendrils during rainy periods in the spring (Fig 3 and 4). Spores from these galls infect apples and crabapples. The smaller, less conspicuous branch galls, with horn-like protrusions shown in Figures 5 and 6, are known as Hawthorn Rust and are caused by the fungus Gymnosporangium globosum. The fungus alternates between Juniperus spp. hosts; and hawthorn, crabapple, and apple in addition to several other rosaceous hosts. Gelatinous swellings on the cedar branches (Figs 7, 8, 9 and 10) are signs of yet another type of rust disease known as Quince Rust, caused by Gymnosporangium clavipes. This disease alternates between[Read More…]
Understanding plant and pest development can help provide the most effective and timely approaches to managing pests.
Everyone loves big, veteran trees. They have a certain distinction and royalty in our forests and landscapes. The first question asked is, “I wonder how old that tree is?” Determination of the actual age of a standing, tree is difficult. There are many methods and techniques. Some are fairly accurate and many are just good guesses.
A group of samples of several varieties of blue holly (Ilex x meservae) arrived in the lab from a commercial nursery in late January with a common problem, yellowing and rapidly dropping leaves and general poor growth (Fig. 1). After ruling out disease and insects on the foliage we next checked the root systems. After washing away most of the soil we started to see areas of black roots (Fig. 2, 3 and 4), especially at the root tips (Fig. 5). Microscopic examination of roots confirmed the suspicion that the plants had black root rot (BRR), caused by the fungus Thielaviopsis basicola. The distinctive black segmented spores (chlamydospores) make it easy to identify in the lab (Fig. 6 and 7) The fungus usually begins by only rotting scattered roots throughout the root system. As it spreads it can cause significant root loss and stunting of susceptible host plants. The pathogen[Read More…]
Q) I have a maple tree (it is either an ‘October Glory’ or ‘Autumn Blaze’) that has what I assume to be a rather large sucker at the bottom. The diameter of the sucker is about 2″ and the tree trunk itself is 7″ in diameter. I have attached pictures of it from different angles. I would like to know if it is ok to remove it? I’ve read quite a bit about these and that late winter/early spring is a good time to remove them. – J.M., Crown Point, IN A) Some landscape plants produce vigorous, upright stems that become troublesome as they out compete better-formed branches and shade out the rest of the plant. These remarkably fast-growing, upright stems are called “suckers” if they come from the root system. You are correct that late winter/early spring before the new growth begins is the best time to try and[Read More…]