Barriers, pest control

Most emphasis is placed on a program of rigorous preventive maintenance. Appropriate climate conditions can help to prevent mold attack, which typically only occurs at elevated relative humidity. Storage furniture which provides an effective barrier for insects, regular inspection of the collections, monitoring of all collection areas with insect traps, and access control measures which minimize the chance of insect entry into the collection areas, are some aspects of an effective pest control management program (175). 

Currently, the only biological barrier registered as a biochemical pest control agent is kaolin, a clay mineral [47]. Kaolin is a ubiquitous clay substance found in soils worldwide and consists of a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra [Al2Si205(0H)4]. 

As indicated earlier H. subflexa has recently become the subject of numerous pest control studies due to the potential for population control of H. virescens by a sterile hybrid release program. However, these two species maintain reproductive isolation despite broadly overlapping ranges and intersecting reproductive periods. Hence, barriers to interspecific gene flow are most likely due to differences in their respective sex pheromone communication systems and, as indicated earlier, there are considerable differences in the pheromone gland contents of each. 

Some pests, diseases, and disorders, and the techniques and materials listed here for prevention and control, are given fuller descriptions, and often pictured, in the chapter on Plant Health (pp.82-103) including mineral (nutrient) deficiencies, biological controls, traps and barriers, and "organic" fungicides and pesticides. Chapter 2, The Soil, contains more information on soil nutrient content and soil chemistry and pH pp.30-33). 

Devices and machines used to control pests or alter their environment are called mechanical controls. Traps, screens, barriers, radiation, and electricity can sometimes be used to prevent the spread of pests or reduce an infestation. Lights, heat, and refrigeration can alter the environment sufficiently to suppress or eradicate some pest populations. 

Mechanical control methods for vertebrate pests include traps, barriers, gunning, attractants, and repellents. 

Barriers—Earners are designed to prevent pests from passing. These include fences, screens, and other barriers which cover openings, stop tunneling, and prevent gnawing. Materials used include sheet metal, hardware, cloth, concrete, asbestos board, and similar materials. This kind of approach is especially effective in control of rodents, bats, and birds in structures. 

Fruit gnawed or eaten. Causes Birds squirrels rats other small animals. Use traps or physical barriers to get rid of rodents netting may be necessary for birds. See Stopping Animal Pests" on page 408 for more information on controlling pests. 

For some pests, using a single control method may be sufficient to prevent damage. Cutworm collars are reliable barriers against cutworms once the spring risk to transplants has passed no further action need be taken. 

The control methods described in this section come from a variety of sources. Some are gardening practices that have been handed down as folklore through the ages, while others are based on the latest scientific research. Many of them are simply matters of common sense—keep your plants healthy and they ll be better able to fend off problems use barriers to exclude pests from your plants and your crops won t be eaten. Regardless of the meth-... 

In general, physical control methods are more often used to control insects than to control diseases. There is a wide variety of traps and barriers that thwart many common insect pests. Physical control of disease organisms is limited to removing diseased plant parts by hand or with pruning tools. 

Trunk bands act as barriers and traps to control pests that crawl along tree trunks on their way to the foliage or to the soil. 

Despite their environmentally desirable qualities, pheromones account for less than 1% of the 6 billion worldwide market for insect control products (5). The two major factors that relegate pheromones to only a few minor market niches are, perversely, their high target specificity, which makes them relatively unattractive in crop systems requiring the control of multiple pest species, and their high cost of synthesis compared to insecticides. The latter factor represents a significant market barrier even in the best of circumstances where only a single pest species predominates. 

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