Chapter VI: Insect Management . Minor insect damage lowers the crop’s value because the market demands clean, unblemished produce. Growers need to quickly recognize insect problems and practice early control to prevent a buildup and keep insect pests from getting out of control.
Insect Life Cycle. Insects either have a complete or incomplete life cycle. Insects in the complete life cycle group have four distinct stages, the egg, larvae, pupae and adult. Examples of these insects are beetles and moths. Beetles lay their eggs either singly or in groups, and they hatch into either grubs or larvae that move about freely on the plant feeding on roots, tubers, leaves, or fruits. After reaching maturity, they then pupate (the resting stage) and develop into adults. Adult beetles also may damage plant parts, so two damaging stages may exist.
Figure VI- 1 depicts growth stages for insects having a complete life cycle. Figure VI- 1. Complete Life Cycle.
Moths and butterflies also have a complete life cycle similar to beetles except that the damaging stage is the larvae or worm stage which usually feeds on the stems, leaves or fruits. The adult stage, moths and butterflies, feed on nectar or may not feed at all. Insects with a complete life cycle almost always have a chewing mouthpart. Insects with incomplete life cycles include grasshoppers and true bugs (stink bug and squash bugs).
Many insects in this category have piercing, sucking mouthparts and suck juice from plants. Some, such as the grasshopper, chew on leaves and stems.
Sesbania grandiflora (Fabaceae) Common Names: Agati `Ohai `ula`ula `Ohai ke`oke`o. Edited 04dec00 jsp; 29may03 ahv; 060808 jsp For more information about this and other plants, please contact your local NRCS field office or Conservation District, and visit the PLANTS Web site<http:// or the. The plant, Amorphophallus titanum, called the Titan Arum or Corpse Plant, is one of six dormant corms donated to Niagara Parks by Louis Ricciardiello of Gilford, New Hampshire, in December 2011. Titan Arum specimen #1. Merritt Lyndon Fernald, of Gray’s Manual of Botany and also co-author of Edible Wild Plants of Eastern North America, wrote twenty years after the above study: “There is no reason, except the odor, that prevents us from.
Back to Crops Grown in Florida. UF/IFAS reprint An Overview of Florida Sugarcane 1 L. Sugarcane is a crop that can be grown throughout Florida. In most areas of the state it is. Places Edible Plants are found are broken up into the following groups. Diseases; Disorders and Diseases of Ornamental Palms; Flowering Plants; Growing Orchids: Easier Than You Think! Your Florida Guide to Bedding Plants; Your Florida Guide to Perennials; Fruits & Vegetables; Banana in Florida.
Regardless, insects with an incomplete life cycle are unique in that they hatch from eggs into tiny nymphs that resemble the adult stage. They stay in the nymphal stage for several weeks, while growing and molting into larger insects until they reach adulthood. Adults have fully developed wings and can fly great distances. Nymphs either do not have wings or have wings that cannot be used for flight.
Insects with an incomplete life cycle can be controlled at any stage, but are easier to control in the nymphal stage just after they hatch from the eggs. Figure VI- 2 depicts the developmental stages of insects with incomplete life cycles. Figure VI- 2. Incomplete Life Cycle. Image courtesy of North Dakota State University. Insect Injury. Insects injure plants by chewing leaves, stems and roots, sucking juices, egg laying or transmitting diseases.
Injury by Chewing Insects. Insects take their food in a variety of ways. One method is by chewing off external plant parts.
Such insects are called chewing insects. It is easy to see examples of this injury.
Perhaps the best way to gain an idea of the prevalence of this type of insect damage is to try to find leaves of plants with no sign of insect chewing injury. Cabbageworms, armyworms, grasshoppers, the Colorado potato beetle and the fall webworm are common examples of insects that cause chewing injury.
Injury by Piercing- Sucking Insects. Another important method which insects use to feed on plants is piercing the epidermis (skin) and sucking sap from cells. In this case, only internal and liquid portions of the plant are swallowed, while the insect feeds externally on the plant. These insects have a slender and sharp pointed part of the mouthpart which is thrust into the plant and through which sap is sucked. This results in a very different but nonetheless severe injury. The hole made in this way is so small that it cannot be seen with the unaided eye, but the withdrawal of the sap results in either minute white, brown or red spotting on leaves, fruits and/or twigs; leaf curling; deformed fruit; or a general wilting, browning and dying of the entire plant.
Aphids, scale insects, squash bugs, leafhoppers and plant bugs are examples of piercing- sucking insects. Injury by Internal Feeders. Many insects feed within plant tissue during a part or all of their destructive stages.
They gain entrance to plants either in the egg stage when the female thrust into the tissues with sharp ovipositors and deposit the eggs there, or by eating their way in after they hatch from the eggs. In either case, the hole by which they enter is almost always minute and often invisible. A large hole in a fruit, seed, nut, twig or trunk generally indicates where the insect has come out, and not the point where it entered. The chief groups of internal feeders are indicated by their common group names: borers; worms or weevils in fruits, nuts or seeds; leaf miners; and gall insects. Each group, except the third, contains some of the foremost insect pests of the world. In nearly all of them, the insect lives inside the plant during only a part of its life and emerging sooner or later as an adult. Control measures for internal feeding insects are most effective if aimed at adults or the immature stages prior to their entrance into the plant.
A number of internal feeders are small enough to find comfortable quarters and an abundance of food between the upper and lower epidermis of a leaf. These are known as leaf miners. Gall insects sting plants and cause them to produce a structure of deformed tissue. The insect then finds shelter and abundant food inside this plant growth. Although the gall is entirely plant tissue, the insect controls and directs the form and shape it takes as it grows. Injury by Subterranean Insects.
Subterranean insects are those insects that attack plants below the surface of the soil. They include chewers, sap suckers, root borers and gall insects. The attacks differ from the above ground forms only in their position with reference to the soil surface. Some subterranean insects spend their entire life cycle below ground. In other subterranean insects, there is at least one life stage that occurs above the soil surface; these include wireworm, root maggot, pillbug, strawberry root weevil, and corn rootworm. The larvae are root feeders while the adults live above ground.
Injury by Laying Eggs. Probably 9. 5% or more of insect injury to plants is caused by feeding in the various ways just described. In addition, insects may damage plants by laying eggs in critical plant tissues. As soon as the young hatch, they desert the plant causing no further injury. Use of Plants for Nest Materials.
In addition to laying eggs in plants, insects sometimes remove parts of plants for the construction of nests or for provisioning nests. Insects as Disseminators of Plant Diseases. In 1. 89. 2, a plant disease (fireblight of fruit trees) was discovered to be spread by an insect (the honeybee). At present, there is evidence that more than 2. The majority of them, about 1. Insects may spread plant diseases in the following ways: By feeding, laying eggs or boring into plants, they create an entrance point for a disease that is not actually transported by them. They carry and disseminate the causative agents of the disease on or in their bodies from one plant to a susceptible surface of another plant.
They carry pathogens on the outside or inside of their bodies and inject plants hypodermically as they feed. The insect may serve as an essential host for some part of the pathogens life cycle, and the disease could not complete its life cycle without the insect host. Examples of insect vectored plant diseases are shown below.
Disease. Vector Fireblight (bacterial) Pollinating Insects Tomato curly top (virus) Beet leafhopper Cucumber mosaic (virus) Aphids. Benefits and Value of Insects.
Insects must be studied carefully to distinguish the beneficial from the harmful. Producers have often gone to great trouble and expense to destroy insects, only to learn later that the insect destroyed was not only harmless, but it was actually engaged in saving their crops by eating destructive insects. Insects are beneficial to the vegetable grower in several ways: Insects aid in the production of vegetables by pollinating the blossoms. Melons, squash and many other vegetables require insects to carry their pollen before fruit set.
Parasitic insects destroy other injurious insects by living on or in their bodies and their eggs. Insects also act as predators, capturing and devouring other insects.
Insects destroy various weeds in the same ways that they injure crop plants. Insects improve the physical condition of the soil and promote its fertility by burrowing throughout the surface layer. Also, the dead bodies and droppings of insects serve as fertilizer. Insects perform a valuable service as scavengers by devouring the bodies of dead animals and plants and by burying carcasses and dung.
Many of the benefits from insects enumerated above, although genuine, are insignificant compared with the good that insects do fighting among themselves. There is no doubt that the greatest single factor in keeping plant- feeding insects from overwhelming the rest of the world is that they are fed upon by other insects. Insects that eat other insects are considered in two groups known as predators and parasites. Predators are insects (or other animals) that catch and devour other creatures (called the prey), usually killing and consuming them in a single meal. The prey generally is smaller and weaker than the predator. Parasites are forms of living organisms that live on or in the bodies of living organisms (called the hosts) from which they get their food, during at least one stage of their existence.
The hosts usually are larger and stronger than the parasites and are not killed promptly but continue to live during a period of close association with the parasite. Predators are typically very active and have long life cycles; parasites are typically sluggish and tend to have very short life cycles.
Insect Control. Insect control is also important to keep the pests from spreading to other crops, and it may help reduce the incidence of disease by killing insect vectors. Insects attacking vegetables can be divided into three categories: Soil Insects. Chewing Insects. Sucking Insects. Soil Insects. Soil insects include wireworms, white grubs, fire ants, cutworms, seed maggots and the sweet potato weevil.