Quebec Apple Orchards Research Articles

Pest Activity and Protection Practices: Four Decades of Transformation in Quebec Apple Orchards.

Simple SummaryCommercial orchards from Quebec (Canada) were followed for over 40 years to track patterns of activity of major fruit pests, fruit damage and impacts (environmental and financial) of pesticide applications. Some insects (as expected) were more prevalent in the insecticide-free orchard than in commercial orchards, while others were (surprisingly) more prevalent in commercial orchards or as prevalent in both orchard types. Annual fruit damage in the insecticide-free orchard was extremely high (as much as 98% for a single pest) and mostly from the apple maggot, the plum curculio and the codling moth. In commercial orchards, fruit damage was ten times less important and mostly from the plum curculio, the tarnished plant bug and the oblique-banded leafroller. The number of registered pesticides, the number of applications and the total cost of pesticides gradually increased from 1977 to 2019, while the environmental and health risks followed a downward trend for most pesticide categories. The historical trends presented here were likely modulated by external factors such as the pesticide regulatory framework, the arrival of non-native insects and climate change.A group of commercial orchards from Quebec (Canada) was followed from 1977 to 2019 as part of a project to implement Integrated Pest Management (IPM) practices. Collected data comprised activity of major fruit pests (from monitoring traps), fruit damage at harvest and pesticide applications, from which the annual costs and impacts of protection programs over 42 years were calculated. Activity and fruit damage in commercial orchards were compared to patterns observed in a reference insecticide-free orchard. Some insects (European apple sawfly, codling moth, apple maggot) were more prevalent in the insecticide-free orchard than in commercial orchards, while others were more prevalent in commercial orchards (oblique-banded leafroller) or as prevalent in both orchard types (tarnished plant bug). Annual fruit damage in the insecticide-free orchard was mostly from the apple maggot (up to 98%), the plum curculio (up to 90%) and the codling moth (up to 58%). The average situation was different in commercial orchards, whose damage was mostly from the plum curculio (up to 7.6%), the tarnished plant bug (up to 7.5%) and the oblique-banded leafroller (up to 1.7%). While the number of registered pesticides, the number of applications and the total cost of pesticides gradually increased from 2002 to 2019, the risks incurred, as measured by indicators of environmental and health impacts, followed a downward trend for insecticides and acaricides and varied slightly for fungicides.

Seasonal biology and behaviour of the predatory mirid Hyaliodes vitripennis, a beneficial insect of apple orchards in Quebec, Canada

Seasonal biology and behaviour of the predatory mirid <i>Hyaliodes vitripennis,</i> a beneficial insect of apple orchards in Quebec, Canada

Parasitoid guild and parasitism rate of the obliquebanded leafroller in IPM orchards and adjacent woodlands

The obliquebanded leafroller (OBLR), Choristoneura rosaceana (Harris) [Lepidoptera: Tortricidae], a primary pest in Quebec apple orchards, can be naturally parasitized. Knowing that habitats around crop’s peripheries are reservoirs for natural enemies of pests, the objective of the present investigation was to assess parasitism and parasitoid guild composition associated with the OBLR. The two-year study included orchards under integrated pest management, their edges, and adjacent woodlands. Parasitism was assessed using sentinel OBLR larvae and considered spring, early summer and late summer. Parasitism rates between regions with different vegetation composition were not significantly different. The first year, late summer larvae showed higher parasitism in orchards (27%), compared to edges (7%) and woodlands (11%). The following year, larvae exposed in early summer had higher parasitism rate in edges (28%) compared to orchards and woodlands (17% in both zones). Nineteen parasitoid species parasitized sentinel larvae. The tachinid Actia interrupta (Curran), the most abundant species, represented 28 and 62% of species the first and the second year respectively. Our research demonstrates that natural biological regulation of the OBLR is the result of a highly diversified parasitoid guild and this should be taken into account in any Integrated Pest Management program.

Differential sensitivity of an invasive and an indigenous ladybeetle to two reduced‐risk insecticides

AbstractThe invasive multicoloured Asian lady beetle, Harmonia axyridis (Pallas), and the indigenous twelve spotted lady beetle, Coleomegilla maculata DeGeer (Col., Coccinellidae), are two important generalist predators commonly found in apple orchards in Quebec, Canada. Both species are exposed to two reduced‐risk insecticides, recently adopted to control codling moth, Cydia pomonella (L.) (Lep., Tortricidae) in south‐eastern Canada. Chlorantraniliprole (Altacor® 35 WG), an anthranilic diamide insecticide, causes paralyses of the muscle cells by interfering with the insect ryanodine receptors, whereas novaluron (Rimon® EC 10), a benzoylphenyl urea, inhibits the chitin synthesis. The aim of this study was to compare the sensitivity of both the invasive ladybeetle H. axyridis and the indigenous C. maculata to reduced‐risk insecticides through the assessment of lethal effect on eggs and larvae following topical contact, ingestion of treated prey and exposure to fresh residues, at field rates (50.75 g a.i./ha chlorantraniliprole and 100 g a.i./ha novaluron) in laboratory conditions. Eggs of both species were not affected. Following 6 days of residual contact, chlorantraniliprole and novaluron caused more than 98% mortality to larvae of both ladybeetle species. In topical contact and ingestion trials, chlorantraniliprole caused less than 18% mortality to larvae of the two species after 6 days following exposure. Novaluron had a drastically different impact on the two predators. It did not affect the indigenous C. maculata, whereas it killed 91% and 96% of H. axyridis individuals after 6 days, respectively, following topical contact and ingestion. These results illustrate a differential sensitivity to novaluron between two relatively close species (subfamily Coccinellinae), a potential impact on the invasion process by H. axyridis, and consequently on the ladybeetle assemblage in the field.

Susceptibility in field populations of codling moth,Cydia pomonella(L.) (Lepidoptera: Tortricidae), in Ontario and Quebec apple orchards to a selection of insecticides

Codling moth is a major pest of pome fruit worldwide. Insecticide resistance has become a widespread pest management issue. However, the current status of insecticide resistance in Ontario and Quebec codling moth populations is unknown. Codling moth populations were collected from 27 orchards in Ontario and Quebec from 2008 to 2010. A series of laboratory bioassays were performed to establish baseline susceptibility of adults and larvae to azinphos-methyl, thiacloprid, chlorantraniliprole and methoxyfenozide. Adult codling moth percentage mortality ranged from 22 to 97% and from 21 to 85% when exposed to topical bioassays using azinphos-methyl and thiacloprid respectively. Azinphos-methyl LC50 values from three selected orchards were ca fivefold greater than those from an insecticide-susceptible population. Neonate larva percentage mortality ranged from 5 to 50%, from 15 to 65%, from 90 to 100% and from 10 to 40% when exposed to diet bioassays using azinphos-methyl, thiacloprid, chlorantraniliprole and methoxyfenozide respectively. Based on the response of the field-collected populations, resistance development to some registered insecticides was evident in some Ontario and Quebec populations. With the present status of insecticide resistance documented in these regions, modifications to codling moth management strategies should be initiated before changes in field efficacy occur.

A note on the activity and species composition of sesiids [Lepidoptera: Sesiidae] as measured by pheromone traps and trunk sampling in apple orchards of southwestern Quebec

Adult males and larvae of sesiids were monitored in ten (1989–1991), five (2000) and two (2004) Quebec apple orchards. Multi Pher III traps baited with 99.1% Z, Z-3, 13-octadecadienyl acetate and 0.9% Z, E plus E, Z-3, 13-octadecadienyl acetate were used for adults, and trunk sampling was used for larvae. Synanthedon scitula, S. pyri, Podosesia syringae, S. acerrubri, S. fulvipes, S. exitiosa, S. acerni and Sesia tibialis males were captured between 1989 and 1991. Only 5 of the 347 adults of the S. scitula/pyri complex captured in 2000 belonged to S. pyri.

Occurrence of Grapholita molesta (Lepidoptera: Tortricidae) in major apple-growing areas of southern Quebec

AbstractOriental fruit moth (Grapholita molesta (Busck) (Lepidoptera: Tortricidae)) adult males were captured by pheromone traps in 10 of 24 orchards monitored in southern Quebec from 2003 to 2005. Twelve, 22, and 133 oriental fruit moths were captured in 2003, 2004, and 2005, respectively. One oriental fruit moth larva was collected in each of two orchards in 2004. This is the first record of this species in Quebec apple orchards.

Attract and kill, an effective technique to manage apple maggot, Rhagoletis pomonella [Diptera : Tephritidae] in high density Quebec apple orchards

"Attract and kill" is an effective technique to control apple maggot (Rhagoletis pomonella) in apple orchards. It provided 98.5 to 100% clean fruit at harvest in McIntosh, Liberty, Royal Gala and Jonagold cvs. The traps consisted of yellow boards (28 cm x 21.5 cm) sandwiched between the two halves of red spheres (9 cm diam). They were sprayed with 12.5 and 6.3% cypermethrin or 1.3 and 1.7% deltamethrin in de-odorized kerosene, loaded with butyl hexanoate in semi-permeable sachets. The traps were hung on branches 1.20-1.70 m above the ground. They were placed on the periphery of the plot and positioned so as to be visible from outside the tree canopy. The number of traps per plot was a function of the length of the plot opposite a possible entry site of apple maggot. In columns opposite a forest, entry site of apple maggot into the plot, the traps in a column were at 2-3 m intervals (0.3-0.5 traps m-1). A trap was also placed on every tree of the first and last row of a column. The columns were 4-5.5 m apart (0.18-0.25 traps m-1). Opposite to prairie grass or a chemically treated plot the traps were at 2-6 m intervals (0.17-0.5 traps m-1) in a column. On the row, the distance between adjacent traps was 4 to 12 m (0.08-0.25 traps m-1). To achieve commercially acceptable apple maggot control in cvs. McIntosh, Liberty, Gala and Jonagold apples with "attract and kill" technique, the activity of the pest should not exceed 13 flies per four traps placed on the periphery of the plot, in other words, 1.6 times the action threshold for the apple maggot in Quebec apple orchards.

Impact of intraguild predation and lambda‐cyhalothrin on predation efficacy of three acarophagous predators

This laboratory study reports the interaction of three predators found in commercial apple orchards in Quebec, Hyaliodes vitripennis (Say) (Hemiptera: Miridae), Harmonia axyridis Pallas (Coleoptera: Coccinellidae) and Amblyseius fallacis (Garman) (Acarina: Phytoseiidae). First, intraguild predation between H vitripennis and the two other predators was characterized in the absence and presence of their extraguild prey, Tetranychus urticae Koch. The results showed an asymmetrical interaction in favour of the larger predator and the levels of intraguild predation were weak for the two predatory combinations. Presence of the phytophagous mite reduced the intensity of intraguild predation in the predatory combination of H axyridis and H vitripennis. Second, the effects of intraguild predation and the application of lambda-cyhalothrin on predation efficacy of the predators were evaluated. The application of the insecticide reduced prey consumption of H vitripennis and H axyridis but did not affect that of A fallacis. Combination of predators and an insecticide application resulted in two different situations depending on the species involved: a reduced predation efficacy for the combination of H vitripennis and H axyridis due to a knockdown effect caused by the insecticide, and no effect on T urticae consumption for H vitripennis and A fallacis. It is suggested that an integrated pest management program based on H vitripennis, A fallacis and lambda-cyhalothrin may be evaluated to repress phytophagous mites in Quebec orchards.

Soil nitrate levels as influenced by apple orchard floor management systems

Mulches are an alternative to herbicidal control of weeds in orchards. Mulches may affect soil nutrient levels and consequently alter tree growth, fruit yield, and quality. The objective of this study was to determine the effects of cultivation, straw mulch, geotextile mulch, grass cover, a cover crop mixture of lupin and wild carrot, and manure compost mulch on extractable soil nutrients in two newly established dwarf apple orchards in Quebec. In 1992, manure compost and straw mulches resulted in higher soil NO3−-N and K relative to those levels under ground cover. Levels of soil NO3−-N were related to soil water content under any particular mulch. Straw mulch resulted in high July NO3−-N levels and low September levels of soil NO3−-N. Geotextile and cultivation treatments resulted in higher September NO3−-N levels relative to July. Soil under manure compost tended to have higher P levels than soil under other treatments. There was little or no effect of mulch treatments on extractable levels of soil NH4+-N, Ca, or Mg. Key words: Orchard, apple, mulches, geotextiles, straw, nutrients, manure compost, grass sod

Impact of soil management systems on organic dwarf apple orchards and soil aggregate stability, bulk density, temperature and water content

With growing pressure to reduce pesticide use, fruit growers require an alternative to herbicidal control of weeds. One option is the use of mulches or permanent vegetative ground covers, which in turn may have advantages in promoting soil physical properties and improving growth. This study examined the short-term effects of ground cover management in two newly established dwarf apple orchards in Quebec. Effects of cultivation, composted manure mulch, straw mulch, grass cover crops, a cover crop mixture of lupin and wild carrot (mixed flora) and geotextile were determined, comparing soil aggregate stability, bulk density, temperature, volumetric water content and tree growth. Straw and geotextile mulches resulted in higher soil water contents and tree growth relative to soil under grass or mixed flora ground cover. Ground cover maintained soil aggregate stability. Soil temperatures were highest under cultivation and geotextile treatments in spring and summer months, and apple yields and growth rates were greater than for ground cover treatments. Straw mulch buffered soil from temperature variation. Little effect of mulch treatments on soil bulk density was observed. Given that soil water content was the primary factor related to optimum orchard production straw and geotextile mulches promoted soil water retention and could be considered superior management options for growers, depending on costs of establishment and maintenance of the mulches. Key words: Mulches, ground cover, bulk density, aggregate stability, soil temperature, volumetric water content

Robust Binomial Decision Rules for Integrated Pest Management Based on the Negative Binomial Distribution

It is time consuming and expensive to count all pests on each sample unit in an integrated pest management (IPM) program to estimate mean abundance of pests. Binomial sampling using only the percentage of leaves containing any pests has been recommended on many occasions as a viable short cut, although, as shown here, this procedure can be misleading. It is possible, however, to set up a binomial procedure based on the percentage of samples with more than T pests ( T > 0). If the pest species follows the negative binomial distribution, there is an optimal value of T for which the binomial scheme is most robust with respect to the value (within a prespecified range) of k , the second parameter of the negative binomial distribution. The procedure is exemplified by using IPM data for tetranychid mites in Quebec apple orchards.

ATTRACTION OF MALE GREEN APPLE BUGS, LYGOCORIS COMMUNIS (HEMIPTERA: MIRIDAE), TO CAGED FEMALES

In Quebec apple orchards, pheromones are used to monitor a number of pest species (Rivard et al. 1978; Paradis et al. 1979). However, few studies have looked for the presence of sex pheromones in mirids. Scales (1968) detected the presence of sex pheromone in a mirid, Lygus lineolaris (P. de B.), as did Strong et al. (1970) for Lygus hesperus Knight. Subsequently, the daily and annual cycles of pheromone emission in Distantiella theobroma (Dist.) (King 1973) and Helopeltis clavifer (Walker) (Smith 1977) were established.

To dodine ofVenturia inaequalisisolates from Nova Scotia and Quebec apple orchards

to dodine of<i>Venturia inaequalis</i>isolates from Nova Scotia and Quebec apple orchards

Distribution of Plant-Parasitic Nematodes in Quebec Apple Orchards

VRAIN, T. C., and G. L. ROUSSELLE. 1980. Distribution of plant-parasitic nematodes in Quebec apple orchards. Plant Disease 64:582-583. In a survey of apple orchards in southeastern Quebec in 1978, 351 soil samples were collected from 71 orchards in nine counties. Species in eight genera of plant-parasitic nematodes were found. Species of Pratylenchus, Paratylenchus, and Xiphinema were detected most frequently. Pratylenchuspenetrans or Pratylenchus crenatus were found in all 71 orchards, at densities greater than 33/100 cm 3 of soil in 58% of infested samples. Xiphinema americanum was found in 88% of the orchards. Quebec is a major apple-growing province of Canada, producing about 110,000 metric tons annually on 8,000 ha. Most orchards are 20- to 30-yr-old trees on standard rootstocks such as Malus robusta 5 or seedlings (12). High density plantings on size-controlling rootstocks are gradually replacing the old orchards. Apple trees with union necrosis and decline have been found in Quebec (13,14). A virus closely related to tobacco ringspot virus was isolated from affected trees, and Xiphinema americanum, a vector of this virus, was always present in the rhizosphere of those trees. Because of the potential for damage to new orchards by Pratylenchus penetrans (9) or by X. americanum, this survey was undertaken to determine their distribution and density in apple orchards of southern Quebec.

Sampling and Distribution of Summer Eye-spotted Bud Moth Spilonota ocellana (D. &amp; S.), Larvae and Nests on Apple Trees

Summer larvae of the eye-spotted bud moth, Spilonota ocellana (D. and S.), appeared in unequal densities on certain portions of apple trees in Door County, Wisconsin. The resulting non-random distribution introduced a bias in data obtained of the summer larvae. This phenomenon has been reported in Quebec apple orchards (LeRoux and Reimer, 1959) where densities of summer larvae were consistently greater in the upper than in the lower tree levels, and quadrant differences often occurred in the number of eggs parasitized, spring and summer larval shelters, and pupal shelters. The present study was initiated to determine the extent of the uneven distribution of summer eye-spotted bud moth larvae and nests on young, non-bearing apple trees. Summer larvae appear shortly after the first of August when eggs begin to hatch (Oatman, 1960).