• Assessing the Risk of Insecticide Resistance in Citrus Thrips in Arizona

      Kerns, David L.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 2004)
      Bioassay with Dimethoate, Carzol, Danitol, Baythroid and Success were conducted on citrus thrips collected from the Yuma Mesa to determine if insecticide resistance to these insecticides occurred. Low to moderate levels of resistance were detected for Dimethoate, Carzol and Danitol, and one population exhibited a high level of resistance to Baythroid. No resistance was evident for Success. Susceptibility to Success was much higher for the Yuma populations relative to populations previously reported in California.
    • Chemical Control and Integrated Pest Management of Woolly Whitefly

      Kerns, David L.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 2004)
      Five foliar insecticide treatments (Esteem, two rates of Provado, two rates of Applaud, Prev-am, and Danitol + Lorsban) were evaluated for their control of woolly whitefly infestations in grapefruit. All of these products demonstrated efficacy in mitigating woolly whitefly populations. Danitol + Lorsban was the best knock-down treatment evaluated, but for sustained control, Esteem appeared to be most effective. Applaud demonstrated good activity, but the rate we tested may be a little low; the 1.0 lb/ac rate should be evaluated. Provado at 19 oz/ac was a good treatment, while the 10 oz/ac rate appears to be sub-par. Prev-am is a oil based contact material and demonstrated good initial activity. Soil injections of 16 and 32 oz/ac of Admire were very effective against WWF, and there were no detectable differences between the two rates. Previous experiments with soil injections of Admire in citrus suggested that as much as six weeks needs to pass before the trees have enough time to adequately take up the Admire from the soil. However, these data suggest that smaller trees, about 10 ft tall, may require as little as two weeks to pick up the material.
    • Chemical Control and Integrated Pest Management of Woolly Whitefly

      Kerns, David L.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 2007-10)
      Eight foliar insecticide treatment regimes (single applications of Esteem, Danitol + Lorsban, Applaud, Provado and Prev-am, and two applications of Applaud, Provado, and Prev-Am) were evaluated for management of woolly whitefly infestations in grapefruit. All of these products demonstrated efficacy in mitigating woolly whitefly populations. Danitol + Lorsban appeared to be the best knock-down treatment evaluated, but Provado and Prev-Am also demonstrated good activity. For sustained control, all of the treatments were effective; however, Prev-Am required an additional application to achieve equivalent control. Soil injections of 16 and 32 fl-oz/ac of Admire were very effective against WWF, and there were no detectable differences between the two rates. The Admire appeared to require about 27 days after injection to demonstrate consistent activity.
    • Chemical Control of Citrus Thrips on Lemons in the Low Desert Areas of Arizona

      Kerns, David L.; Maurer, Michael; Langston, Dave; Tellez, Tony; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 1997-11)
      Insecticides were evaluated for their efficacy to citrus mealybugs on lemons at three spray gallonages, 60, 240, and 600 gallons per acre. None of the products tested exhibited any activity at 60 or 240 gallons per acre. At 600 gallons per acre, Lorsban at 6 qt/A + NR-415 oil at 1.4% v/v, Supracide at 2 pt /100 gal + Kinetic at 0.25% v/v, and Applaud at 2.0 lbs -ai/A + NR -415 oil at 1.4% v/v all demonstrated the best activity. Provado at 0.1 lbs-ai/A + NR-415 oil at 1.4 %, Danitol at 0.4 lbs-ai/A + Lorsban at 4 qt/A + NR-415 oil at 1.4% v/v, and Nexter at 0.3 lbs-ai/A + NR-415 oil at 1.4% v/v showed good activity. Weaker treatments included Agri-Mek at 10 and 20 oz/A, Knack and Difenolan. For maximum control, growers should treat before the fruit is heavily infested, and use high gallonages of spray solution at a high pressure, the spray must penetrate the waxy coating to achieve activity. If applicable, a spray oil should be included to help break up the wax. However, if Supracide is used, use a high rate without oil.
    • Commercial Evaluation of M-96-015 for Control of Citrus Mealybug, Woolly Whitefly and Citrus Thrips in Lemons

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      M-96-015 did not appear to effectively control woolly whitefly but does appear to kill citrus mealybug. However, as with other insecticides coverage is a problem. The real benefit of M-96-015 towards citrus mealybug would occur if it prevented their spread. However, we were not able to measure this in this study. As with previous trials, M-96-015 is an effective citrus thrips material.
    • Control of Early Woolly Whiteflies Infestations with Foliar Insecticides

      Kerns, David L.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 2003)
      Five foliar insecticide treatments (Esteem, Provado, Applaud, Assail, and Danitol + Lorsban) were evaluated for their control of early woolly whitefly infestations in lemons. Esteem and Applaud are insect growth regulators that should have little impact on whitefly parasitoids. The impact of Provado and Assail on whitefly parasitoids is not certain, but at high rates may be detrimental, while Danitol + Lorsban will be especially harmful to parasitoids. The impact of these insecticides on woolly whitefly could not be fully determined in this trial due to the effectiveness of parasitoids, Eretmocerus comperei or E. dozieri (exact species not certain), on controlling the whiteflies in this test. However, other research (not reported here) has indicated that all of the insecticide treatments evaluated have good activity against woolly whitefly. Because parasitoids can be extremely effective in mitigating woolly whiteflies populations during the early phases of colonization, it is recommended that chemical control not be utilized until woolly whitefly colonies are common. However, previous experiences suggest that allowing woolly whitefly populations develop extremely high populations should be avoided.
    • Devoloping an Action Threshold for Citrus Thrips on Lemons in the Low Desert Areas of Arizona

      Kerns, David L.; Maurer, Michael; Langston, Dave; Tellez, Tony; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 1997-11)
      Commercial and University citrus groves were sampled over a two year period in an attempt to develop mathematical models capable of predicting fruit scarring based on the population of immature citrus thrips on susceptible fruit. Five predictive models were derived. One model correlated used citrus thrips populations from fetal fall to 2.0 in. diameter fruit. While in the other models, thrips populations were divided into four distinct fruit size cohorts. Four of the five models were statistically valid. Based on these models, lemons ½ in. in diameter, should be treated with insecticides when the number of immature CT reaches 1.5 per 10 pieces of fruit. While fruit > ½ should be treated if immature CT reach or exceed 2.0 per 10 fruit.
    • Efficacy of Insecticide to Citrus Thrips on Lemons in the Low Desert Areas of Arizona

      Kerns, David L.; Maurer, Michael; Langston, Dave; Tellez, Tony; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 1997-11)
      New chemistries (Alert, Success, Fipronil, Ni -25, Nexter, Danitol and Baythroid) were evaluated and compared with standard chemistries (Agri-Mek, Dimethoate and Carzol) for control of citrus thrips in lemons grown in the Yuma area. Additionally, Success was compared to Carzol in a large plot commercial demonstration. Under cool, early season conditions, all products appeared to offered good thrips control. However, under warmer conditions, Nexter, Danitol, Baythroid and Dimethoate appear weak. Among the new insecticides, Success and Fipronil appear most efficacious. Alert also appeared to have good activity at the high rate, but appeared to offer shorter residual control than Fipronil or Success. Fipronil was the only new product tested that flared mites. However, rotating sulfur into the Fipronil applications appeared to help prevent flaring. Growers can expect Baythroid and Danitol to behave similarly to Dimethoate for efficacy and residual control. Under commercial conditions, Success provided thrips control equivalent to Carzol at 1.38 lbs-ai/A.
    • Efficacy of Insecticides to Citrus Thrips on Lemons in Yuma Arizona 1997

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      Three small plot efficacy trials were conducted evaluating different insecticide rotation regimes using commercially available insecticides and the effectiveness of new insecticide chemistries to control citrus thrips. Because of its long residual activity, and ability to control post- application egg hatches, Carzol appears to be the product that best fits the petal fall application window. Agri-Mek, Baythroid, Dimethoate or Vydate are probably good follow -up insecticides. However, Agri-Mek and Baythroid will probably provide greater control, especially under hotter conditions. If temperatures are cool, Agri-Mek looks good at reduced rates. The best insecticide for subsequent applications depends on temperatures and what was previously applied. Avoid making back -to -back applications of the same materials, and Dimethoate or Vydate applications should probably be followed by Carzol to catch post- application egg hatches. Overall, Vydate appears to be very similar to Dimethoate in efficacy and residual activity, while Baythroid appears to be slightly better. Although the addition of Lannate to Dimethoate does slightly enhance thrips control, the additional cost probably does not justify the tank mix. Of the new chemistries (Alert, Success, Ni-25, and M-96-015) evaluated, Success and M-96-015 appeared to offer the best fruit protection. However, M-96-015 does not appear to be very effective in killing the thrips, but is very effective in repelling them. Also, M-96-015 will need to be applied at a high gallonage, i.e. 500 gal/A. None of the new products tested appear to fit the petal fall application window very well. Ni-25, Alert and Success appear to lack the residual activity of Carzol, and M-96-015 should not be used as a clean-up material but preventively following Carzol at petal fall.
    • Efficacy of Insecticides to Citrus Thrips on Lemons in Yuma Arizona 1998

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1999-11)
      Two small plot efficacy trials were conducted evaluating different insecticide rotation regimes using commercially available insecticides and the effectiveness of new insecticide chemistries to control citrus thrips. Under the consistently cool conditions experienced during the first four weeks of the trial, Dimethoate, Success, Baythroid, Agri-Mek, Vydate and Carzol all of the offered adequate control and would fit well in the petal fall window. This is in contrast with previous years experiences when high temperatures within a week of petal fall would result in all treatments except Carzol requiring a re-treatment within ten days. All of the rotation schemes evaluated required three insecticide applications to get through the season, and did not appear to be greatly different in controlling thrips and producing high quality fruit under the environmental conditions experienced. However, the Dimethoate - Success - Baythroid rotation scheme was most cost effective. When temperatures were in the 70's to low 80's, Dimethoate and Vydate offered about three weeks control, Success, Carzol, Baythroid and Agri-Mek all offered about four weeks control. When temperatures were in the mid to upper 80's and low to mid 90's, Success provided about three weeks control while Carzol didn t require re-treatment for 4 weeks. Under these same temperature conditions, Dimethoate and Vydate gave about 7 to 12 days control, and Agri-Mek provided 12 to 14 days of control. Other than the one control failure with Baythroid, under warmer conditions, it provided about seven days control. In the experimentals test, AZEXP1 appeared to offer knockdown activity at temperatures less than 90 F, and only suppression at higher temperatures. AZEXP2, appeared to be a viable citrus thrips material, with activity similar to Success and Carzol. The knockdown activity of M96 appeared to be enhanced by including Dimethoate or Carzol, but will require multiple applications to achieve the level of repellency experienced in 1997.
    • Evaluation of Insecticide Applications for Citrus Thrips Control Under Hot Conditions

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 2002-02)
      A small plot efficacy trial was conducted evaluating citrus thrips control under hot conditions. Average daily maximum temperatures ranged from the mid-90’s to low 100°F’s. Success and Carzol were the most efficacious products evaluated, followed by Lorsban and Dimethoate. Both Lorsban and Dimethoate provided good initial thrips control but were short lived. Lorsban appeared to have a slightly longer residual than Dimethoate. Both of the pyrethroids, Baythroid and Danitol, performed poorly. Neither provided good thrips knockdown or residual control. Pyrethroids should be avoided for thrips control when temperatures equal or exceed 95°F. We were not able to demonstrate any adverse effect on efficacy towards thrips by acidifying Success. However, Success is not prone to hydrolysis at high pHs, and acidification is not necessary or advised.
    • Evaluation of Milestone Herbicide for Early Post-emergence Weed Control in Citrus on the Yuma Mesa

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 1998-09)
      When applied early-postemergence, Milestone at 0.75 and 1.0 lbs-ai/A provided excellent control of summer annual grasses and broadleaf weed for as long as 4 months, equivalent to Karmex. Princep and Krovar also provided good weed control but appeared to offer slightly shorter residual against some broadleaf species. Solicam, although it provided good weed control, particularly of the grasses, was the weakest material evaluated in this trial. Although Karmex is notorious for causing crop injury on the sandy soils of the Yuma Mesa, we did not detect any injury from this herbicide or any others in this trial.
    • Evaluation of Pre-Petal Fall Citrus Thrips Control

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 2002-02)
      A small plot trial was conducted to evaluate the benefit of applying insecticides for citrus thrips management pre-petal fall. Because of low thrips densities during the pre-petal period, we were not able to discern tangible benefits from making prepetal applications. However, in situations where fruit is present and petal fall has not fully occurred, these applications may be useful to protect these fruit. Of the acute toxicants evaluated pre-petal fall (Assail and Success), Assail appeared to be the best choice. However, if temperatures are approaching 95°F, Assail should be avoided. Pre-petal fall applications of Surround and Snow are beneficial in respect that several applications of these products may be required to obtain adequate coverage, and by making these applications during the pre-petal fall period, thrips can be managed before many susceptible fruit are present.
    • Insecticidal and Yield Enhancement Qualities of Surround Particle Film Technology in Citrus

      Kerns, David L.; Wright, Glenn C.; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 2002-02)
      Surround WP was evaluated at various spray volumes to determine if volumes lower than the label recommended volume of 250 gallon per acre would provide equivalent citrus thrips control and yield enhancement potential. All the spray volumes evaluated (50, 100, 150, and 250 gpa) appeared to be equally effective. It appears that as long as the spray coverage appears to be visually adequate, then coverage is sufficient. Application of Surround WP led to some increase in fruit size, particularly for the first harvest.
    • Insecticidal Control of Woolly Whiteflies

      Kerns, David L.; Wright, Glenn; Gibson, Rick (College of Agriculture, University of Arizona (Tucson, AZ), 2002-11)
      Four foliar insecticides (Esteem, Provado, Applaud and Assail) and one soil systemic insecticide (Admire) were evaluated for their control of woolly whitefly in lemons. These insecticides were chosen for evaluation because they have demonstrated efficacy to other whitefly species and have little or no impact on whitefly parasitoids. Admire was injected with a single shank about 5-in deep around each tree approximately at the tree’s drip line. All of the foliar insecticides were effective in controlling woolly whitefly. Admire also appeared to have efficacy, but due to inconsistent data on one sample date more testing should be conducted. Six weeks after the beginning of this test, whitefly parasitoids, Eretmocerus comperei or E. dozieri (exact species not certain) reduced the whitefly population across all treatments. Within two more months, no live whiteflies could be found in the test grove, and as of July 15, 2002, there was still no detectable woolly whitefly activity.
    • Insecticide Rotation and Pre-Petal Fall Applications for Citrus Thrips Management

      Kerns, David L.; Tellez, Tony; Wright, Glenn; Kilby, Mike (College of Agriculture, University of Arizona (Tucson, AZ), 2000-10)
      Under low citrus thrips pressure and cool temperatures, Alert, Baythroid, Carzol, Success and Acetamiprid applied at petal fall were all effective control agents. Mid-season applications of Baythroid and Danitol were also effective but appeared to be slightly inferior to Success and Alert in residual control. Despite the prolonged blooming and petal drop period experienced during this trial, plots receiving pre-petal fall applications of Acetamiprid did not produce higher quality fruit than treatments where applications began following petal fall. The fact that thrips densities were low during this period may be the reason. Before pre-petal fall insecticide applications can be deemed useful and economically justifiable, evaluations must be made at higher thrips infestation levels.
    • Integrated Pest Management of Citrus Mealybug

      Kerns, David L.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 2004)
      Foliar-applied insecticides and the soil-applied insecticide, Admire, were evaluated for their ability to control citrus mealybug on lemons while having a minimal impact on parasitoids. All of the foliar-applied insecticide exhibited activity towards citrus mealybug. The standard insecticide, Lorsban, performed very well, but since this product is especially harmful to parasitoids it is not considered to have a good fit in IPM programs where parasitoid conservation is emphasized. The currently labeled alternative, Applaud, was an effective treatment and should be considered for citrus mealybug control to avoid destruction of parasitoids. Several experimental insecticides showed promise: NNI-850, NNI-750C and NNI-010. However, NNI-0101 at the lower rate of 0.24 lbs-ai/ac appeared to be weak. The addition of narrow range crop oil, NR-415 at 1.0 gal/ac, appeared to be beneficial for initial mealybug knock-down, especially for the slower acting insecticides such as Applaud. Soil injection of Admire at 16 and 32 oz/ac appeared to have very good activity, but due to variability in the mealybug population, more data should be collected to confirm this finding.
    • Mite Control and Damage to Arizona Citrus

      Kerns, David L.; Wright, Glenn (College of Agriculture, University of Arizona (Tucson, AZ), 2003)
      Lemons were left untreated or treated for mites with Danitol (fenpropathrin). Mite populations were estimated and yield and fruit damage was accessed. Yuma spider mite, Eotetranychus yumensis, was the predominate mite species present during the high fruit susceptibility period. Although there was no apparent impact of mites on yield in this study, there was significant fruit damage that could be attributed to Yuma spider mite. The damage appeared as bronzed colored pitting of the fruit peel. Based on damage ratings, the treated plots produced 56% fancy, 34% choice, and 10% fruit grade based on mite damage, whereas the untreated plots produced 47%, 31% and 22% fancy, choice and juice grade fruit respectively. Statistically, the treated plots produce more fancy and less juice fruit, but did not differ in choice fruit. Although the treated areas produced better quality fruit, the amount of damage suffered in those plots was higher than desired. Fruit in the treated plots likely suffered some mite damage before treatments were initiated. In addition to the fruit damage test, a miticide efficacy test targeting Yuma spider mite on lemon was conducted comparing Agri-Mek, Danitol, Kelthane, Microthiol, and Nexter to an untreated check. Agri-Mek, Nexter, and Microthiol offered 14 days of control; although at 6 DAT Agri-Mek and Nexter did not differ from the untreated. Danitol and Kelthane contained fewer mite that the untreated for at least 35 DAT.
    • Particle Film Technologies: Pest Management and Yield Enhancement Qualities in Lemons

      Kerns, David L.; Wright, Glenn C.; Wright, Glenn (2003)
      Surround WP and Snow were evaluated for their ability to manage citrus thrips populations in lemons on the Yuma Mesa, and their impact on lemon yield, fruit quality, and packout. Both Surround and Snow effectively controlled citrus thrips and prevented fruit scarring. Surround produced higher yields than either Snow or the commercial standard at the first harvest (#9 ring). There were no differences in yield among treatments for the second (strip) harvest, nor were their any differences in total yield. These data suggest that Surround may increase fruit earliness or sizing. There were no statistical differences among any of the treatments in fruit size frequency or quality for any of the harvests, and there was no apparent benefit from applying an additional application of Surround or Snow post thrips season solely for quality, fruit size, or yield enhancement. The activity of Surround does not appear to be adversely affected by the inclusion of the insecticides Danitol, Baythroid, Carzol, or Success, nor do these insecticides appear to be adversely affected by Surround. Foliar fertilizers did not appear to adversely affect the activity of Surround when tank mixed. However, there is some evidence that Surround may negatively affect the absorption of Fe and Mn when tank mixed with Zn, Fe, Mn lignosulfonate, but this data is not conclusive. The addition of a non-ionic surfactant appears to enhance the on-leaf distribution of Surround over light petroleum and paraffin based oils, but long term efficacy is not affected.
    • Pest Management and Yield Enhancement Qualities of Particle Film Technologies in Citrus

      Kerns, David L.; Wright, Glenn C.; Wright, Glenn; Gibson, Rick (College of Agriculture, University of Arizona (Tucson, AZ), 2002-11)
      Surround WP and Snow were evaluated for their ability to manage citrus thrips populations in lemons on the Yuma Mesa, and their impact on lemon yield, fruit quality, and packout. Both Surround and Snow effectively controlled citrus thrips and prevented fruit scarring, but their ability to manage Yuma spider mite was inconclusive. Preference tests indicated that both Surround and Snow act primarily by repelling the thrips, but also induce some mortality. Surround produced higher yields than Snow at the first harvest (#8 ring), but did not differ from the commercial standard. There were no differences in yield among treatments for the strip harvest, nor were their any differences in total yield. These data suggest that Surround may have some yield or increased fruit earliness enhancement qualities and that Snow may be slightly detrimental. There were no statistical differences among any of the treatments in fruit size frequency or quality for any of the harvests, and there was no apparent benefit from applying an additional application of Surround or Snow post thrips season solely for quality, fruit size, or yield enhancement.