Problems of Herbaceous
Plants
Dr. Curtis E. Swift, Area Extension Agent (Horticulture)
Colorado State University Extension Tri River Area
- The Black Vine Weevil Otiorhynchus
sulcatus (Fabricus)
This insect is seldom seen since the adult feeds at night, but it can
cause considerable damage to flowers, shrubs and greenhouse plants. The adult
notches the edges of leaves while the more damaging larvae feeds on the roots
of the host plant.
- The Geranium Budworm (Heliothis
(syn. Heliocoverpa) virescens)
The Geranium Budworm is a serious pest of cotton, tomato and flowers.
Photographs of the larvae and damage caused, as well as a discussion of the
problem, plants involved and control options are provided.
- Edema (Oedema)
The water-engourged cells of houseplants and greenhouse crops are indicative
of this problem. Photographs of the symptoms and a discussion of the problem
and its' control are provided.
- Hollyhock Rust - Puccinia
malvacearum
Hollyhock rust is a serious problem in many ornamental plantings. Symptoms
of this fungus initially appear as light yellow-orange spots on the upper
surface of leaves of the hosts. The various hosts are listed and control options
are provided.
- The Hornworm
About 1100 species of this insect are found around the world. The moths
feed on nectar of many plants in late afternoon. The adult moths are mostly
medium to large in size, and are sometimes referred to as hawk moths or hummingbird
moths because of their rapid wing beats and hummingbird appearance. The larval
stage (caterpillars) are known as hornworms and feed on many different plants.
- Impatiens Necrotic Spot Virus (INSV)
INSV is a devastating virus problem of many greenhouse plants. Photos
of symptoms and a listing of known susceptible plants are provided.
- A comparison of various
mulches; temperature relationships and plant growth
- A rubber-based mulch was compared with three bark/wood mulches and bare
non-mulched soil to determine the surface temperatures of each, the soil
temperature below each mulch, as well as the leaf temperature and overall
growth of plants in the mulched areas. Surface mulch temperatures as high
as 173 degrees Fahrenheit were recorded. Plant growth was not negatively
affected at these temperatures. All mulches examined maintained soil temperatures
consistently cooler than occurred in non-mulched soil.
- Slime Mold - Myxomycetes - a problem associated with organic mulches
This strange colorful growth on bark mulches is often thought to be
due to a sick dog. A photo of one species of fungi (Myxomycetes) and a discussion
of the Myxomycetes is provided.
WebMaster Dr.
Curtis E. Swift, Area Extension Agent, Horticulture
Colorado State University Extension
2775 US Hwy 50, Grand Junction, CO. 81503
voice: 970-244-1834
fax: 970-244-1700