Fruit Tree Red Spider Mite Research Articles

Anystis baccarum: An Important Generalist Predatory Mite to be Considered in Apple Orchard Pest Management Strategies.

The increasing concern over the continued use of pesticides is pressurising apple growers to look for alternatives to chemical pest control. The re-discovery, and subsequent conservation, of the beneficial predatory mite, Anystis baccarum (Linnaeus) (Acari: Anystidae), in Bramley apple orchards in Northern Ireland offers a potential alternative control component for incorporation into integrated pest management strategies. Anystis baccarum readily feeds upon economically important invertebrate pest species including European fruit tree red spider mite, Panonychus ulmi (Koch) (Acari: Tetranychidae) and show a level of compatibility with chemical pesticides. Recent mis-identification by apple growers of this beneficial mite species had resulted in unnecessary pesticide applications being applied within Northern Irish apple orchards. However, dissemination of information to the apple growers and promotion of the benefits this mite offers in apple orchards has helped to conserve its populations. Apple growers, across the United Kingdom, must be encouraged to be aware of A. baccarum, and indeed all predatory fauna, within their orchards and seek to conserve populations. In doing so, it will ensure that the British apple market remains an environmentally sustainable production system.

Ecological benefits of Anystis baccarum in an orchard ecosystem and the need for its conservation

Integrated pest management programs are very important in the control of invertebrate pests within apple orchards. Many current integrated pest management strategies concentrate on specialist predatory species. However, generalist beneficial insects, such as several mite species, must also be fully researched for their potential in controlling pests. Previous research has shown that the generalist predatory mite Anystis baccarum (Linnaeus) can offer much potential in controlling invertebrate pests within Northern Irish apple orchards. However, apple growers have been mis-identifying this beneficial species as the economic pest European fruit tree red spider mite, Panonychus ulmi (Koch). As a result, unnecessary pesticide applications have been applied against what has now been confirmed as a beneficial species. To aid apple growers in the identification of A. baccarum, identification cards were produced. Positive uptake of the cards by many apple growers has resulted in correct identification of A. baccarum from P. ulmi, and therefore, a reduction in chemical pesticide applications. The benefits of A. baccarum within orchard ecosystems is discussed.

Comparison of the effectiveness of standard and drift-reducing nozzles for control of some pests of apple

A comparison of the biological efficacy of pesticides applied against some apple pests with standard versus drift-reducing nozzles was made in trials in intensive orchards in Slovenia. Standard and drift-reducing nozzles were compared by applying 350L spray per hectare. No significant differences in acaricide/insecticide efficacy between the types of nozzles could be observed when controlling fruit tree red spider mite (Panonychus ulmi) and apple rosy aphid (Dysaphis plantaginea). However, drift-reducing nozzles reduced the efficacy of insecticides against the codling moth (Cydia pomonella), green apple aphid (Aphis pomi) and apple leaf miner (Leucoptera malifoliella).

Functional response of Euseius finlandicus and Amblyseius andersoni to Panonychus ulmi on apple and peach leaves in the laboratory.

The functional response of adult females of the predatory mites Euseius (Amblyseius) finlandicus and Amblyseius andersoni to larvae and adult females of the fruit tree red spider mite Panonychus ulmi was determined on apple and peach leaf disks in the laboratory at 25 degrees C and 16:8 (L:D). For adult females of P. ulmi the predation efficiency of E. finlandicus was higher on peach than on apple, whereas that of A. andersoni was higher on apple than on peach. Efficiency of predation on larvae of P. ulmi by either predator did not differ significantly between apple and peach. On both plants, A. andersoni had a higher predation rate than E. finlandicus on larvae of P. ulmi. It is concluded that in the laboratory the host plant has a substantial effect on predation efficiency of A. andersoni and E. finlandicus when they preyed on adults but not when they preyed on larvae of P. ulmi.

Diapause Induction and Termination in Eggs of the Fruit Tree Red Spider Mite Panonychus Ulmi in Northern Greece

In apple orchards in northern Greece, females of Panonychus ulmi Koch were found to lay diapause eggs from late August to the beginning of October. The course of diapause termination in the field was determined by transferring diapause eggs during winter and early spring from apple orchards with the varieties ‘Starkinson’ and ‘Firiki’ to short days (LD 8:16) (1992–1996), and long days (LD 16:8) (1994–1995), both at 20 °C. Percentages of diapause termination were very low to zero from October to the beginning of January, then progressively increased throughout January and February. Diapause termination in 50% of the eggs occurred in the first half of February in lowland mite populations irrespective of the year and location from which the eggs originated, and about one month earlier in a population originating from an altitude of 300 m. For each sampling date throughout the winter, the mean number of days required for 50% egg hatch at 20 °C (T50%) was similar under either a long (LD 16:8) or a short (LD 8:16) photoperiod. Diapause eggs collected in October 1995 from two orchards and maintained at 0, 5, 10 and 15 °C for various periods were subsequently transferred to 20 °C and LD 8:16, where TP50% was determined. It was shown that temperature, duration of maintenance at the different temperatures and the orchard from which the eggs originated had a significant effect on T50% and therefore on diapause development. Additionally, in our strains diapause intensity was much weaker than in strains from more northern latitudes and was terminated even without any cold exposure. The variation in diapause intensity in different strains of P. ulmi may have an adaptive significance for this widespread species.

Panonychus ulmi . [Distribution map

Abstract A new distribution map is provided for Panonychus ulmi (Koch) Acarina: Tetranychidae. (European red mite, fruit tree red spider mite). Attacks deciduous fruit and forest trees. Information is given on the geographical distribution in Europe, Austria, Belgium, Bulgaria, Czech Republic, Denmark, Finland, France, Germany, Hungary, Irish Republic, Italy, Netherlands, Norway, Poland, Portugal, Romania, Sicily, Spain, Sweden, Switzerland, Turkey, United Kingdom, Yugoslavia, Africa, Algeria, Egypt, Libya, South Africa, Tunisia, Russia, Kabardino-Balkaria, Krasnodar, Leningrad region, Ossetia region, CIS (former USSR), Armenia, Azerbaijan, Belarus, Georgia, Kyrgyzstan, Latvia, Lithuania, Moldova, Ukraine, Asia, Afghanistan, China, Beijing, Gansu, Hebei, Henan, Hubei, Hunan, Jiangsu, Liaoning, Nei Menggu, Ningxia, Qinghai, Shaanxi, Shandong, Shanxi, Sichuan, India, Himachal Pradesh, Jammu & Kashmir, Uttar Pradesh, Iran Israel, Japan, Korea, Lebanon, Syria, Taiwan, Australasia and Pacific Islands, Australia, New South Wales, Queensland, South Australia, Tasmania, Victoria, New Zealand, North America, Canada, Alberta, British Columbia, Manitoba, New Brunswick, Nova Scotia, Ontario, Prince Edward Island, Quebec, Saskatchewan, USA, California, Connecticut, Colorado, Delaware, Florida, Georgia, Idaho, Iowa, Illinois, Indiana, Kansas, Kentucky, Maine, Maryland, Massachusetts, Michigan, Minnesota, Missouri, Montana, New Hampshire, New Jersey, New York, North Carolina, Ohio, Oregon, Pennsylvania, Rhode Island, Tennessee, Utah, Vermont, Virginia, Washington, west Virginia, Wisconsin, Central America and Caribbean, Bermuda, Costa, Rica, South America, Argentina, Brazil, Parana, Rio Grande do Sul, Santa Catarina, Chile, Uruguay, Venezuela.

Cross-resistance between flucycloxuron, clofentezine and hexythiazox in Panonychus ulmi (fruit tree red spider mite)

Between 1988 and 1992, 26 strains of Panonychus ulmi (fruit tree red spider mite) were collected from fields in which control failures had been observed with the acaricides clofentezine, hexythiazox or flucycloxuron.

Effects of repeated foliar sprays of insecticides or gungicides on organophosphate-resistant strains of the orchard predatory mite Typhlodromus pyri on apple

In field experiments in commercial apple orchards in southern England in 1990 and 1991, foliar sprays of the pyrethroid insecticide cypermethrin or the organophosphate insecticide pirimiphos-methyl at commercially recommended rates were harmful to organophosphate-resistant strains of the orchard predatory mite Typhlodromus pyri, leading to increases in its prey, the fruit tree red spider mite, Panonychus ulmi. Repeated sprays of the fungicides dinocap, maneb plus zinc, thiophanate-methyl, benomyl or captan, or of the carbamate insecticide carbaryl or the organophosphate insecticide chlorpyrifos, did not significantly affect predator numbers. Inconclusive results were obtained with mancozeb. The toxicity of carbaryl was not affected by addition of an adjuvant containing rapeseed oil. The toxicity of chlorpyrifos or pirimiphos-methyl was not altered by spraying at medium (500 l ha −1) or low (100–150 l ha −1) volumes.

Mite-management programmes based on organophosphate-resistant Typhlodromus pyri in UK apple orchards

In a 4-year trial in apple orchards, the effectiveness of the predatory mite Typhlodromus pyri as a biological control agent against the fruit tree red spider mite, Panonychus ulmi, and the apple rust mite, Aculus schlechtendali, was examined under different pesticide regimes. T. pyri survived insecticide programmes based on organophosphates or carbaryl and, in the third and fourth year of the OP programme and the fourth year of the carbaryl programme, regulated phytophagous mite populations to such an extent that no acaricides were necessary. In plots treated with a synthetic pyrethroid insecticide programme, few T. pyri were found and acaricide treatments were required in each year. A pest-management system that integrates this biological control of phytophagous mites with chemical treatment for other pests is described.

Do phytoseiid mites select the best prey species in terms of reproductive success?

Optimal foraging theory predicts that predators prefer those prey species that are most rewarding in terms of reproductive success, which is dependent on prey quality and prey availability. To investigate which selection pressures may have moulded prey preference in an acarine system consisting of two prey species and three predator species, we tested whether prey preference of the predators is matched by the associated reproductive success. The predators involved areAmblyseius finlandicus (Oudemans),Am. potentillae (Garman) andTyphlodromus pyri Scheuten. The prey species are the apple rust mite (Aculus schlechtendali (Nalepa)) and the fruit-tree red spider mite (Panonychus ulmi (Koch)). Reproductive success was assessed in terms of intrinsic rate of increase and for one predator also in terms of diapause induction. All three predator species reached highest reproductive success on the same prey species: apple rust mite. This was most pronounced for the predatorAm. finlandicus, because its larval stage suffered severe mortality when feeding onP. ulmi. An independent study on prey preference of the three predator species (Dicke et al., 1988) revealed thatAm. finlandicus prefersAc. schlechtendali toP. ulmi, whereas the other two predator species have the reverse preference. Thus, on the basis of current data, prey preference ofAm. finlandicus can be understood in terms of reproductive success. However, this is not so for prey preference ofT. pyri andAm. potentillae. Investigations needed for a better understanding of prey preference of the last-named two predator species are discussed.

Supervised control of apple pests in southern England

Supervised control involving use of insecticides and acaricides only when assessments showed that these were necessary, was compared with normal spray programmes applied to apple tree plots of at least 0·4 ha on 23 sites for 1–5 years at each site, giving a total of 57 trials. Pest assessments and spray thresholds were adapted from those in use in the Netherlands in 1974. The growers' usual insecticides and acaricides were used in the supervised programmes when necessary and their normal fungicidal programmes were used. Pests reaching the spray threshold included aphids (rosy apple, apple-grass, green apple, rosy leaf-curling, and woolly), apple sucker, common green capsid, winter moth, apple sawfly, tortricids (fruitlet mining, fruit tree, and summer fruit), codling moth and fruit tree red spider mite. Minor pests included common earwig, apple leaf midge and green and brown leaf weevils. An average of 3·2 insecticides and acaricides was applied per annum to the supervised plots compared with 5·0 in the growers' programmes. The greatest savings were pre-blossom and at petal fall. Little pest damage to foliage was recorded with either programme. Approximately 4·1 % of fruit on the supervised plots showed pest damage (on a severe assessment) compared with 2·9% with the growers' programmes. Supervised control saved 10·78% of growers' normal pesticide costs; it can prevent serious pest damage while utilizing smaller amounts of insecticides and acaricides.

Codling moth granulosis virus: effects of its use on some other orchard arthropods

SUMMARYIn four field trials from 1978 to 1980, sprays of codling moth granulosis virus (CpGV) plus 1·0% skimmed milk powder did not significantly affect damage to fruit by leaf rollers (tortrix moths). In laboratory tests, survival of larvae of the leaf roller Archips podana fed on leaves sprayed with CpGV plus milk was unaffected and they grew faster than on unsprayed leaves, because of the milk deposits. This might increase damage by A. podana if CpGV plus milk were applied during the feeding period of this species. In one field trial an unusual infestation of fruit by larvae of pith moth Blastodacna atra was not affected by CpGV. Azinphos‐methyl significantly reduced damage by B. atru and, in one field trial where sprays were correctly timed, that by leaf rollers. CpGV had no consistently significant effects on numbers of fruit tree red spider mite Panonychus ulmi or its predators, whereas azinphos‐methyl induced outbreaks of P. ulmi by killing its predators.

Resistance to binapacryl and tetradifon, and the genetic background, in fruit tree red spider mite, Panonychus ulmi, from English apple orchards

SUMMARYAssays on eggs of Panonychus ulmi held on leaf discs of Myrobalan plum were used to characterise strains (1) multi‐resistant to organophosphates (OPs) and binapacryl (strain BR), (2) multi‐resistant to OPs and tetradifon (strain TR), and (3) susceptible to OPs, binapacryl and tetradifon (strain EM). By crosses of EM females and BR males, and of EM females and TR males, and by repeated backcrossing with EM males under selection pressure of the acaricides concerned, two strains were produced in which the specific genes for resistance to binapacryl and tetradifon were isolated in the genome of the EM strain. Reciprocal crosses of the resulting backcrossed strains with EM, assays on the F1 eggs and the F2 haploid eggs, confirmed the presence of single major genes for resistance to binapacryl and tetradifon, and the absence of maternal effects. The expression of gene BR was incompletely dominant in response to binapacryl, whilst gene TR was effectively dominant in response to tetradifon.Eggs of the field‐derived strain BR showed c. 50× resistance to binapacryl, 8–19 × to dinobuton, but only c. 2× to dinocap and dinoseb. The backcrossed strain was less resistant (26 ×) to binapacryl implying that resistance in strain BR was augmented by the effects of minor genes. Resistance to tetradifon (150–200 × on eggs) involved cross‐resistance to tetrasul (23 ×) and to chlorfensulphide (27×); resistance in the field‐derived strain appeared to depend on the major gene alone.Resistance mechanisms were highly specific in their effects, so that there was no cross‐resistance to unrelated acaricides, including amitraz, dicofol, cyhexatin, formetanate, chlordimeform, and quinomethionate. Fecundity of strain BR was 44% less than that of EM; laboratory and field evidence suggest that multi‐resistant mites tend to be less fit than susceptible mites. The practical implications are discussed.

Resistance to organophosphates, and the genetic background, in fruit tree red spider mite, Panonychus ulmi, from English apple orchards

SUMMARYAssays on adult females and eggs of Panonychus ulmi, on leaf discs of Myrobalan plum, were used to characterise and establish homogenous organophosphateresistant (OR) and susceptible strains. Reciprocal crosses of these strains, and assays on adult mites and eggs of the parent, F1 and F2 generations confirmed that resistance was controlled by a single major gene, the expression of which was dominant in the response to parathion, and incompletely dominant to vamidothion, dimethoate and demeton‐S‐methyl. Reproductive incompatibility, between strains, as in Tetranychus urticae, was not found.Bioassays on larvae hatched from winter eggs, collected from several orchards in Kent, Essex and Somerset, were used to evaluate the spectrum of cross‐resistance to a range of 20 organophosphates (OPs). Together with assays on adult females, these tests showed 10‐ to 100‐fold resistance to most of the OPs used for several years including those noted above, but less than 10‐fold to azinphos compounds and to several recently‐introduced OPs, e. g. dialifos, triazophos, dioxathion. The resistance spectrum in strain OR and five field strains was similar, but some had higher levels to parathion and demeton‐S‐methyl, and others to dioxathion after 3–4 years' exposure. Resistance levels to individual OPs may be enhanced by specific selection. Strains resistant to OPs showed only 2‐ to 5‐fold resistance to two carbamates, and were fully susceptible to dicofol.

Multiple nozzles for producing small drops in a mist‐blower spray machine

AbstractThe biological effectiveness of deposits of binapacryl applied by a single high pressure nozzle was compared with similar deposits applied by twin low‐pressure nozzles. Equal foliar deposit densities were obtained from the two systems but the single nozzles gave marginally better control of apple powdery mildew and fruittree red spider mite.

Predator–prey Systems with Mites1)

AbstractPopulation models of fruit tree red spider mite and predatory mite are given, which are used to explain the regulation of spider mites by predatory mites and may be used to manage spider mite systems in apple orchards.The models are based on extensive experimental knowledge of the bionomics of prey and predator. A detailed analysis of the prey–predator relations on the individual level paved the way for the development of prey–predator models on the population level. These models, based on the state variable approach, simulate the population fluctuations: of prey and predator in dependence of the changing abiotic factors during the season using time steps of a quarter of an hour and trace all state variables, as the number of eggs, larvae, adult females and gut content of the adult female predator. Verification of the models at different levels of integration showed good agreement between model output and the results of independent experiments, and this enabled a sensitivity analysis with the model. This sensitivity analysis showed the relative importance of different factors, so that management strategies to achieve tolerable prey–predator levels throughout the year may be developed.

Codling moth

Control of codling moth with modern insecticides, although successful, depends mainly on broad‐spectrum chemicals that kill many natural enemies which could otherwise contribute to the control of codling moth and other pests, notably the fruit tree red spider mite. Research on populations of codling moth at Long Ashton contributed information needed to develop integrated control, utilising predators, parasites and pathogenic organisms in combination with selective pesticides

A comparison of the efficiency of sprays of two drop‐size ranges in an apple orchard

AbstractA two‐season trial of a mist blower‐sprayer with improved air‐flow characteristics was made to assess the relative efficiency of 120 and 180 μm mass median diameter (MMD) drop‐size sprays for the control of apple powdery mildew (Podosphaera leucotricha) and fruit tree red spider mite (Panonychus ulmi Koch) in a hedgerow‐type apple orchard. The principal pesticide was binapacryl, applied at two rates for each drop‐size. Under typical commercial conditions the smaller drop‐size approximately halved the incidence of apple mildew found when the conventional 180 μm MMD drop‐size spray was used; there was no conclusive advantage against red spider mite. Unexpectedly large variations occurred in the deposits from the weekly applications and were related to the humidity during spraying.

A rapid technique for analysing diets of invertebrate predators by electrophoresis

SUMMARYA technique has been developed for the rapid determination of some species of prey consumed by mites and insects. The method detects prey enzymes within the gut of a predator by polyacrylamide gradient gel electrophoresis and subsequent staining for esterase activity. It is sufficiently sensitive to detect fruit tree red spider mite (Panonychus ulmi) esterases within the gut of a single predacious mite (Typhlodromus pyri) for at least 31 h after feeding. The method has been used to demonstrate feeding relationships among a range of insect and mite predator and prey species in the laboratory and in the field.

Predation of Codling Moth Eggs, Cydia pomonella, the Predators Responsible and Their Alternative Prey

12-86%4 of codling moth eggs glued to the leaves and fruit of a cider-apple orchard at weekly intervals throughout the summer were sucked out, and 3-29%4 disappeared. The mortality of the natural population of eggs is estimated to be lower than this, because in laboratory tests all predators were less likely to feed on naturally-laid eggs than on glued ones. The numbers and biomass of six species of Heteroptera and one mite able to suck out the contents of codling moth eggs, and the numbers of earwigs, which are thought to be responsible for egg disappearance, were recorded in the foliage. Because of their low numbers, codling eggs are not thought to be an important food source for these predators. The major prey of heteropteran predators is probably the fruit tree red spider mite, Panonychus ulmi, because their numbers and weights fluctuated in relation to the abundance of this prey, and no other. It is concluded that the heteropteran predators of P. ulmi also usefully reduce the abundance of codling moth eggs and subsequent damage to the fruit.