Esteban Basoalto

Use of Glacial Acetic Acid to Enhance Bisexual Monitoring of Tortricid Pests With Kairomone Lures in Pome Fruits

ABSTRACT Studies were conducted to assess glacial acetic acid (GAA) with various host plant volatiles (HPVs) and the sex pheromone, (E,E)-8, 10-dodecadien-1-ol, of codling moth, Cydia pomonella (L), as lures in traps for tortricid pests that often co-occur in tree fruits in the western United States. In addition to codling moth, field trapping studies were conducted with oriental fruit moth, Grapholita molesta (Busck), obliquebanded leafroller Choristoneura rosaceana (Harris), the leafroller Pandemis pyrusana Kearfott, and the eyespotted budmoth, Spilonota ocellana (Denis and Schiffermüller). HPVs included ethyl (E,Z)-2,4-decadienoate (pear ester), (E)-4,8dimethyl-l,3,7-nonatriene, butyl hexanoate, (E)-&bgr;-ocimene, (E)-&bgr;-farnesene, and farnesol. Three types of GAA co-lures differing in a 10-fold range in weekly evaporation rates were tested. The evaporation rate of GAA co-lures was an important factor affecting moth catches. The highest rate tested captured fewer codling moth but more leafrollers and eyespotted budmoth. GAA co-lures caught both sexes of each species. The field life of butyl hexanoate and (E)-&bgr;-ocimene lures were much shorter than pear ester or sex pheromone lures. Adding GAA to pear ester or to (E)-&bgr;-ocimene significantly increased the catches of only codling moth or oriental fruit moth, respectively. Combining pear ester or (E) -&bgr;-ocimene with GAA did not affect the catch of either species compared with the single more attractive HPV. Adding HPVs to GAA did not increase the catches of either leafroller species or eyespotted budmoth. Traps baited with pear ester, sex pheromone, and GAA for monitoring codling moth were also effective in classifying pest pressure of both leafroller species within orchards.

Improving the Performance of the Granulosis Virus of Codling Moth (Lepidoptera: Tortricidae) by Adding the Yeast Saccharomyces cerevisiae with Sugar

ABSTRACT Studies were conducted with the codling moth granulosis virus (CpGV) to evaluate whether adding the yeast Saccharomyces cerevisiae Meyen ex E. C. Hansen with brown cane sugar could improve larval control of Cydia pomonella (L.). Larval mortalities in dipped-apple bioassays with S. cerevisiae or sugar alone were not significantly different from the water control. The addition of S. cerevisiae but not sugar with CpGV significantly increased larval mortality compared with CpGValone. The combination of S. cerevisiae and sugar with CpGV significantly increased larval mortality compared with CpGV plus either additive alone. The addition of S. cerevisiae improved the efficacy of CpGV similarly to the use of the yeast Metschnikowia pulcherrima (isolated from field-collected larvae). The proportion of uninjured fruit in field trials was significantly increased with the addition of S. cerevisiae and sugar to CpGV compared with CpGValone only in year 1, and from the controls in both years. In comparison, larval mortality was significantly increased in both years with the addition of S. cerevisiae and sugar with CpGV compared with CpGV alone or from the controls. The numbers of overwintering larvae on trees was significantly reduced from the control following a seasonal program of CpGV plus S. cerevisiae and sugar. The addition of a microencapsulated formulation of pear ester did not improve the performance of CpGVor CpGV plus S. cerevisiae and sugar. These data suggest that yeasts can enhance the effectiveness of the biological control agent CpGV, in managing and maintaining codling moth at low densities.

Adding yeasts with sugar to increase the number of effective insecticide classes to manage Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) in cherry

BACKGROUND Drosophila suzukii is a major pest of cherry in the western United States. We evaluated whether the addition of sugary baits could improve the efficacy of two classes of insecticides not considered to be sufficiently effective for this pest, diamides and spinosyns, in laboratory and field trials in cherry. RESULTS Adding cane sugar alone or in combination with the yeasts Saccharomyces cerevisiae or Aureobasidium pullulans significantly improved insecticide efficacy. However, the significance of adding yeasts to the sugar plus insecticide on fly mortality varied with respect to both the insecticide and yeast species. The addition of S. cerevisiae to sugar also did not significantly reduce egg densities in fruit compared with sugar alone. The addition of a yeast plus sugar significantly reduced egg densities in three field trials with cyantraniliprole and in two out of three trials with spinosad. CONCLUSION The addition of cane sugar with or without yeast can improve the effectiveness of diamide and spinosyn insecticides for D. suzukii in cherry. Inclusion of these two insecticides in D. suzukii management programs may alleviate the strong selection pressure currently being imposed on a few mode-of-action insecticide classes used by growers to maintain fly suppression over long continuous harvest periods of mixed cultivars. Published 2015. This article is a U.S. Government work and is in the public domain in the USA.

Variability in the efficacy of sex pheromone lures for monitoring oriental fruit moth (Lepidoptera: Tortricidae)

Studies were conducted in Chile and the United States to compare the attractiveness of various commercial sex pheromone lures and two experimental lures for oriental fruit moth, Grapholita molesta (Busck), in peach orchards treated with or without sex pheromone dispensers. The experimental lures contained the three‐component sex pheromone blend of G. molesta: Z‐8‐dodecenyl acetate, E‐8‐dodecenyl acetate and Z‐8‐dodecenol (Z8‐12:OH), and the sex pheromone of codling moth, Cydia pomonella (L.), (E,E)‐8,10‐dodecadien‐1‐ol, (codlemone). Commercial lures varied in their substrate, initial loading and blend ratio of components. Significant differences in male catches were found among commercial lures in orchards treated with or without sex pheromone dispensers. Experimental lures with the addition of codlemone significantly increased the catches of G. molesta using lures loaded with 0%, 1% or 5% Z8‐12:OH in the G. molesta blend compared with the same ratio of components in just the G. molesta blend. The experimental lures were significantly more attractive than all commercial lures in the untreated orchard. However, moth catch with the experimental lures in the sex pheromone‐treated orchard was only intermediate among all of the lures tested. These findings highlight the need to develop more effective and standardized lures that can be used in trap‐based monitoring programme for this important pest.

Development of 2-phenylethanol plus acetic acid lures to monitor obliquebanded leafroller (Lepidoptera: Tortricidae) under mating disruption

We evaluated the effectiveness of 2‐phenylethanol (PET) in combination with acetic acid (AA) as a binary lure for monitoring male and female obliquebanded leafroller, Choristoneura rosaceana (Harris). Studies were conducted in apple, Malus domestica Borkhausen, orchards treated with or without sex pheromone dispensers for mating disruption (MD). Open polypropylene vials, closed membrane cups, and rubber septa loaded with AA and/or PET in varying amounts were first evaluated in a series of trapping experiments. Membrane cups loaded with 800 mg of PET were as effective as 10‐mg septa, but longer lasting, and were comparable to the open vials. A membrane cup AA lure was effective in tests, but further work is needed to increase its release rate and extend its activity. Catches of codling moth, Cydia pomonella (L.), and C. rosaceana were unaffected by combining PET with (E,E)‐8,10‐dodecadien‐1‐ol, the sex pheromone of codling moth, pear ester, (E,Z)‐2,4‐ethyl‐decadienoate and AA lures. Adding (E)‐4,8‐dimethyl‐1,3,7‐nonatriene to this blend to enhance codling moth catch significantly reduced catches of C. rosaceana. PET + AA was a more attractive binary lure than AA plus phenylacetonitrile (PAN) for C. rosaceana. The addition of PET or PAN to traps already baited with the sex pheromone of C. rosaceana significantly reduced male catches. Traps baited with PET + AA placed in blocks not treated with MD caught significantly fewer C. rosaceana than traps baited with sex pheromone. In comparison, sex pheromone‐baited traps in MD blocks caught ≤1 male moth per season which was significantly lower than total moth (>10) or female moth (≥3) catch in these blocks with PET + AA. A high proportion (>70%) of trapped females were mated in both untreated and MD‐treated orchards. Further refinement of this binary, bisexual lure using membrane cup technology may allow the establishment of action thresholds and improve management timings for C. rosaceana.

A Binary Host Plant Volatile Lure Combined With Acetic Acid to Monitor Codling Moth (Lepidoptera: Tortricidae)

ABSTRACT Field studies were conducted in the United States, Hungary, and New Zealand to evaluate the effectiveness of septa lures loaded with ethyl (E,Z)-2,4-decadienoate (pear ester) and (E)-4,8-dimethyl-1,3,7-nonatriene (nonatriene) alone and in combination with an acetic acid co-lure for both sexes of codling moth, Cydia pomonella (L.). Additional studies were conducted to evaluate these host plant volatiles and acetic acid in combination with the sex pheromone, (E,E)-8,10-dodecadien-1-ol (codlemone). Traps baited with pear ester/nonatriene + acetic acid placed within orchards treated either with codlemone dispensers or left untreated caught significantly more males, females, and total moths than similar traps baited with pear ester + acetic acid in some assays. Similarly, traps baited with codlemone/pear ester/nonatriene + acetic acid caught significantly greater numbers of moths than traps with codlemone/pear ester + acetic acid lures in some assays in orchards treated with combinational dispensers (dispensers loaded with codlemone/pear ester). These data suggest that monitoring of codling moth can be marginally improved in orchards under variable management plans using a binary host plant volatile lure in combination with codlemone and acetic acid. These results are likely to be most significant in orchards treated with combinational dispensers. Significant increases in the catch of female codling moths in traps with the binary host plant volatile blend plus acetic acid should be useful in developing more effective mass trapping strategies.

Survey of conspecific herbivore-induced volatiles from apple as possible attractants for Pandemis pyrusana (Lepidoptera: Tortricidae)

BACKGROUND Studies were conducted to identify volatiles released by apple foliage untreated or sprayed with a yeast and from untreated and sprayed foliage with actively feeding larvae of Pandemis pyrusana Kearfott. Field studies then evaluated various combinations of these volatiles when paired with acetic acid as possible adult attractants. RESULTS The most abundant volatiles released following herbivore feeding were four green leaf volatiles (GLVs) and acetic acid. Nineteen volatiles were found to be released in significantly higher amounts from foliage with herbivore damage than from intact leaves. The combination of yeast followed by herbivore injury increased the levels of methyl salicylate and phenylacetonitrile compared with herbivory alone. Levels of acetic acid released were not significantly different among the four treatments. Only phenylacetonitrile and 2-phenylethanol with acetic acid caught similar and significantly more total and female moths than acetic acid alone. Moth catches with 12 other volatiles plus acetic acid were not significantly higher than with acetic acid alone, and were lower than with acetic acid and 2-phenylethanol. CONCLUSION These data show that herbivore injury does not create a unique chemical signal for adults to locate oviposition or rendezvous sites. Instead, moths may cue to the aromatic-acetic acid combination as a nutritional cue to locate sugary resources.

Evaluating the use of phenylacetonitrile plus acetic acid to monitor Pandemis pyrusana and Cydia pomonella (Lepidoptera: Tortricidae) in apple

Abstract Recent studies have demonstrated that key herbivore-induced foliage volatiles from apple, Malus domestica Borkhausen (Rosaceae), can be attractive to conspecific adult male and female tortricid leafrollers when used together with acetic acid lures. Our study reported here was conducted in Washington State during 2013–2014 and assessed the attractiveness of both sexes of the leafroller, Pandemis pyrusana Kearfott (Lepidoptera: Tortricidae), to blends of acetic acid with phenylacetonitrile. Interestingly, traps baited with phenylacetonitrile plus acetic acid caught significantly more males, females, and total moths than the number of males caught in traps baited with a commercial sex pheromone lure. The evaporation rate of the acetic acid co-lure was shown to be an important factor affecting catches of P. pyrusana with phenylacetonitrile. Adding phenylacetonitrile to traps baited with pear ester, ethyl (E, Z)-2,4-decadienoate and acetic acid significantly reduced both total and female moth catches of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae). However, neither C. pomonella nor P. pyrusana catch were impacted when phenylacetonitrile and acetic acid were added to traps baited with pear ester plus (E, E)-8,10-dodecadien-1-ol, the sex pheromone of codling moth. These results support our broader work to develop lures to improve monitoring and management of a number of tortricid pests attacking horticultural crops worldwide.

Acetic acid lure placement within traps affects moth catches of codling moth (Lepidoptera: Tortricidae)

Previous studies have shown that the addition of an acetic acid colure (AA) to traps baited with pear ester, (E,Z)‐2,4‐ethyl‐decadienoate, and codlemone, (E,E)‐8,10‐dodecadien‐1‐ol, the sex pheromone (PH) of codling moth, Cydia pomonella (L.) (Lepidoptera: Tortricidae), (Combo lure) can significantly increase moth catches. A commercial AA colure was developed to be used with the Combo lure using a specialized cardboard lure holder. However, research in 2011 suggested that the addition of the AA colure placed in the holder was reducing moth catches. Studies were subsequently conducted in both North America and South America to examine the factors affecting these unexpected results. Hanging the AA colure from the inside top of the delta trap was found to be a primary factor reducing moth catches of male but not female codling moth. Significantly, more males were caught if the AA colure was placed on the sticky liner of the trap than in the holder. Laboratory and field studies found that this negative effect on moth catches lessens over time with aged AA colures that had lower emission rates. The position of the holder in the trap (upwind or downwind) relative to the direction where moths approached was not a significant factor affecting moth catch with the AA colure. However, the spacing of the lures on the holder was an important factor with significantly higher male catches with lures 5.5 cm apart and the AA lure above the Combo lure than with lures 1.5 cm apart and the Combo lure above the AA lure. Similarly, pinning the Combo lure to the roof of the trap was more effective than the use of the holder with the AA lure on the liner. Standardization of lure placement will be important to fully utilize the use of bisexual, multilure monitoring systems for codling moth and likely for other pests.

Improved monitoring of oriental fruit moth (Lepidoptera: Tortricidae) with terpinyl acetate plus acetic acid membrane lures

Male and female moth catches of Grapholita molesta (Busck) in traps were evaluated in stone and pome fruit orchards untreated or treated with sex pheromones for mating disruption in Uruguay, Argentina, Chile, USA, and Italy from 2015 to 2017. Trials evaluated various blends loaded into either membrane cup lures or septa. Membrane lures were loaded with terpinyl acetate (TA), acetic acid (AA) and (Z)‐3‐hexenyl acetate alone or in combinations. Two septa lures were loaded with either the three‐component sex pheromone blend for G. molesta alone or in combination with codlemone (2‐PH), the sex pheromone of Cydia pomonella (L). A third septum lure included the combination sex pheromone blend plus pear ester, (E,Z)‐2,4‐ethyl decadienoate (2‐PH/PE), and a fourth septum was loaded with only β‐ocimene. Results were consistent across geographical areas showing that the addition of β‐ocimene or (Z)‐3‐hexenyl acetate did not increase moth catches. The addition of pear ester to the sex pheromone lure marginally increased moth catches. The use of TA and AA together significantly increased moth catches compared with the use of only one of the two components. Traps with the TA/AA lure outperformed the Ajar trap baited with a liquid TA plus sugar bait. The emission rate of AA was not a significant factor affecting the performance of the TA/AA lure. The addition of TA/AA significantly increased moth catches when combined with the 2‐PH lure. The TA/AA lure also allowed traps to catch both sexes. Catch of C. pomonella with the 2‐PH lure was comparable to the use of codlemone; however, moth catch was significantly reduced with the 2‐PH/PE lure. Optimization of these complex lures can likely further improve managers’ ability to monitor G. molesta and help to develop multispecies tortricid lures for use in individual traps.