Fruit mites

Many consumers have had the experience of returning flour to the grocer because it was heavily infested with mites. These mites are small (less than 1 mm) and usually whitish and oceur in a wide variety of foods. They have come to be known under such common names as cheese mites, flour mites, the bulb mite, and the dried fruit mite. They also are found in smoked and dried meats and fish. 

The next major discovery in this field, which was the result of a joint research effort in 1968 between M and T Chemicals, Inc., and the Dow Chemical Company in the United States (475, 524), was that tricyclo-hexyltin hydroxide ("Plictran ) possesses a very high activity against certain types of mites, and this compound was subsequently introduced by Dow as an acaricide for use on apple, pear, and citrus-fruit trees. A second triorganotin acaricide, bis(trineophyltin) oxide ("Vendex or "Torque ), has recently been introduced by Shell Chemical Company (476). Two other tricyclohexyltin compounds are currently under de-... 

Use pattern Hexythiazox is a thiazolidinone acaricide which has ovicidal, larvicidal and nymphicidal activities against many kinds of phytophagous mites infesting pome fruits, stone fruits, citrus, vegetables and other food crops. On these mites, hexythiazox works by both contact and stomach action... 

Croft, B.A., S.C. Hoyt, and RH. Westigard. 1987. Spider mite management on pome fruits revisited organotin and acaracide resistance management. Jour. Econ. Entomol. 80 304-311. 

Beneficial insects associated with fruit orchards show different responses to diflubenzuron treatment (Broadbent and Pree 1984). Lacewings (Chrysopa oculata) in contact with leaves containing 300 mg/kg DW had reduced survival and inhibited molting of first instar larvae, but the assassin bug (Acholla multispinosa) was not affected by contact with treated leaves. Lacewings and other beneficial predator insects fed diflubenzuron-treated, two-spotted spider mites (Tetrany-chus urticae) for 3 days showed no adverse effects after 14 days (Broadbent and Pree 1984). 

In Cuba and the Central American countries, russeting represents no particular problem, as they produce fruit only for the internal market and the buyers are accustomed to it. In fact, many of the buyers prefer it, under the impression that it is sweeter—a belief that is not without foundation, since the rust mites tend to destroy the resistance of the peel to water loss, resulting in a more concentrated juice through the evaporation of water from the fruit. However, rust mites tend to reduce fruit sizes and also the size of the crop, so control is desirable. 

Several inferences can be drawn from these data that may suggest the impacts to be expected at the consumer and decomposer levels. Accelerated leaf drop may influence the development of pests—namely, aphids, scale insects, and red citrus mites. Pest populations might be increased if injured leaves had higher concentrations of amino acids or free sugars before abscission (see Chapter 11) or diminished if leaves fell too rapidly. Leaf and fruit drop would provide a larger substrate for populations of decomposer organisms at the soil surface. 

Use Nonsystemic insecticide and acaricide for control of sucking and chewing insects and spider mites on vegetables, fruits, ornamentals, field crops, greenhouses, gardens, and forestry. 

Pyrethrum refers to the oleoresin extracted from the dried flowers of Tanacetum cinerariaefolium (Asteraceae) and is the source of the pyrethrins, chrysanthemates and pyrethrates. Among the natural pyrethrins, those incorporating the alcohol pyrethrolone, namely pyrethrins 1 and II (Fig. 9), are the most abundant and account for most of the insecticidal activity. The pyrethrins are recommended for control of a wide range of insects and mites on fruit, vegetables, field crops, ornamentals, glasshouse crops and house plants, as well as in public health, stored products, animal houses and on domestic and farm animals. Pyrethrins are sold in a wide variety of formulations, under many different trade names by a large number of different manufacturers. 

Several species of mites (order Acarina) are effectively controlled by oil sprays. The European red mite, a major pest of fruit in the northeastern United Stat, is a member of this group. This pest appears to have become more severe as a result of the general use of DDT. Such a situation is explained by the fact that mites are not controlled by DDT, while certain parasites and predators of mites are killed by it. The continued use of DDT under these circumstances favors the build-up of mites. 

European red mite Fruit tree leaf roller Apple red bug San Jose scale Scurfy scale... 

Fruit tree leaf roller Pear leaf blister mite Codling moth... 

Two series of petroleum fractions and a series of synthetic isoparaffins prepared by the New York State Agricultural Experiment Station are described briefly. Their insecticidal efficiency on three unrelated pests—oriental fruit moth, European red mite, and cottony peach scale— is reported. 

In the tests with both California red scale and citrus red mite, untreated lots of fruit selected at random from infested fruit prepared for a given day were held with the treated lots and counted for natural mortality. The corrected percentage of kill for each treatment was calculated by means of the Abbott equation (Jf). 

Figures 3 and 4 indicate that the relations of composition and molecular size to the efficiency of petroleum oils against eggs of the citrus r mite are of the same type, with essentially the same critical values, as those foimd by Pearce, Chapman, and Frear (ff) for eggs of the oriental fruit moth. The ovicidal efficiency is nearly constant above a molecular weight of 340 and falls off very rapidly to indeterminate amounts below this level.

It is interesting that the amount of oil deposit required for 95% kill is approximately the same for eggs of the oriental fruit moth and of the citrus red mite. For eggs of the oriental fruit moth, Pearce et al. 21) report lowest minimum effective dosage values of 1.6 mg. per 100 sq. cm. for a paraffinic oil and 2.3 mg. per 100 sq. cm. for a naphthenic oil. Equivalent values for 95% kill of citrus red mite eggs in the present studies were 21 and 15 micrograms per sq. cm., respectively. 

Pearce et al. (21) suggest that some property of the fractions which has not been evaluated is probably related to the killing mechanism of hydrocarbon oils to oriental fruit moth eggs. It is thought that this may be true for eggs of the citrus red mite as well, and may be particularly applicable to the performance of the oils against adult female Califomia red scale. 

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