Evaluation of Insecticides Resistance: Review Article

Pest Management Science, 2012

Insecticide resistance continues to be one of the most important issues facing agricultural production. The challenges in insecticide resistance and its management are exemplified by the situation with the western flower thrips Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This highly invasive pest has a great propensity for developing insecticide resistance because of its biological attributes, and cases of resistance to most classes of insecticides used for its management have been detected. To combat insecticide resistance in the western flower thrips, several insecticide resistance management (IRM) programs have been developed around the world, and these are discussed. Successful programs rely on non-insecticidal tactics, such as biological and cultural controls and host plant resistance, to reduce population pressures, rotations among insecticides of different mode of action classes to conserve insecticide efficacy, resistance monitoring, sampling to determine the need for insecticide applications and education to assure proper implementation. More judicious insecticide use is possible with the development of well-founded economic thresholds for more cropping systems. While growers will continue to rely on insecticides as part of western-flower-thrips-and thrips-transmitted virus management, more effective management of these pests will be achieved by considering their management in the context of overall integrated pest management, with IRM being a key component of those comprehensive programs.

Journal of Economic Entomology, 2008

The western ßower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), has become one of the most difÞcult insects to control in the intensive agriculture of southeastern Spain. However, resistance problems are quite different in two neighboring areas, Murcia and Almeria, with distinct production systems. Thirty-six Þeld populations of western ßower thrips from sweet pepper crops were collected in two different dates in Murcia and Almeria in 2005 and 2006. Western ßower thrips populations collected were exposed to a diagnostic concentration of spinosad, methiocarb, acrinathrin, and formetanate. The results allowed the recognition of higher levels of resistance in Almeria compared with Murcia throughout the growing season. The mortality at the diagnostic concentration for spinosad (120 ppm) in western ßower thrips populations ranged from 34 to 81% in Almeria, and from 73 to 100% in Murcia. The mortalities at the diagnostic concentration to acrinathrin (800 ppm) and formetanate (8000 ppm) were 17Ð31% in Almeria and 77Ð100% in Murcia, and 14 Ð 41% in Almeria and 48 Ð99% in Murcia, respectively, indicating large geographic variations. Toxicity of methiocarb was higher for western ßower thrips populations from both areas. However, mortality at the diagnostic concentration of methiocarb (2000 ppm) varied from 56 to 90% in Almeria, and it was from 94 to 100% in Murcia. The impact of production systems and agricultural practices of each area on the development and stability of insecticide resistance is discussed.

Florida Entomologist, 2014

Newer, selective insecticides with few negative impacts on natural enemies and competitor species are needed for effective, sustainable management of the western flower thrips, Frankliniella occidentalis (Pergande). The purpose of this study was to evaluate the impacts on natural enemies and competitor thrips species of insecticides used for control of western flower thrips in fruiting vegetables. Trials with tomato (Solanum lycopersicum L.) and with pepper (Capsicum annuum L.) were conducted to evaluate insecticide treatment effects on western flower thrips and natural enemies at the North Florida in 2008, 2009, 2010 and 2011. A number of insecticides from different classes showed moderate to high efficacy against western flower thrips. The broad-spectrum insecticides acetamiprid, methomyl, and tolfenpyrad demonstrated activity against the pest, while also reducing populations of the key predator of thrips in pepper, Orius insidiosus (Say) (Hemiptera: Anthocoridae). Insecticides that showed little impact on populations of O. insidiosus were cyantraniliprole, flonicamid, spirotetramat, and terpenes. Although only moderately active against the western flower thrips, they would be valuable additions to existing management programs for pepper. Insecticides with activity against western flower thrips also showed activity against Frankliniella tritici (Fitch). This non-damaging congener species is a beneficial because it out-competes the western flower thrips, especially in tomato where O. insidiosus is not a major factor in western flower thrips management. Numerous insecticides were identified with activity against the western flower thrips that are suitable for use in integrated pest management programs of fruiting vegetables.

2015

This study was conducted to investigate commercial formulations of insecticides against western flower thrips, Frankliniella occidentalis (Pergande).The insects were collected from commercial greenhouses of cucumber in Varamin, Iran. The tested insecticides were diazinon (EC 60%), cypermethrin (EC 40%), fipronil (EC 2.5%), imidacloprid (SC 35%) and a botanical insecticide oxymatrine (Kingbo, AS 0.6%). Fipronil had the highest efficacy among all tested insecticides (LC50 = 17.97 ppm). However, imidacloprid had the lowest efficacy (LC50 = 2303 ppm). The oxymatrine was effective (LC50 = 69.94 ppm) after fipronil.

Australian Journal of Entomology, 2007

Chemical control of western flower thrips Frankliniella occidentalis requires three consecutive applications of the same pesticide, 3-6 days apart. Initially, pesticides recommended for western flower thrips control were based on established maximum residue limits (MRLs) from previously established use on pests other than F. occidentalis, rather than product efficacy against F. occidentalis. Moreover, MRLs were based on a single application rather than three consecutive sprays. Chemical residues associated with the three-spray strategy were not quantified. Here those residues are quantified and the scope for rate increases is further tested, as laboratory bioassays suggest that some current permit rates may be too low to be effective. At established withholding periods (WHPs), current permit rate applications of abamectin (0.018 g/L) on strawberry and tomato, and methidathion (0.5 g/L) and endosulfan (0.666 g/L) on lettuce produced residues above the current Australian MRL. Results indicated that a higher than the current permit rate for endosulfan (2.0 g/L) could be sustained on cucumber and strawberry at established WHPs, but would require an extension to the current WHP. Similarly, a modest increase in methidathion (1.0 g/L) rate on tomato could be practical, again with a WHP extension. In each instance additional supporting data are required to accurately quantify the proposed WHP extensions.

Journal of Economic Entomology, 2009

New pesticides are required to maintain effective resistance management strategies for control of western ßower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). We tested the efÞcacy of acetamiprid, and thiamethoxam, two neonicotinoids that represent a newer class of insecticides for the control of thrips. We also tested chlorfenapyr, a pyrrol compound, and a lower than registered rate of the biopesticide spinosad. Laboratory bioassays were used to predict the relative efÞcacy of insecticides against F. occidentalis and to forecast likely Þeld rates. Two doses within the calculated LC 99.99 range were used to predict Þeld rates and trial rates of 0.5 g and 1.0 active ingredient (AI)/liter acetamiprid, 0.025 and 0.05 g (AI)/liter chlorfenapyr, 0.3 and 0.6 g (AI)/liter thiamethoxam, and 0.01 g (AI)/liter spinosad were tested in the greenhouse against pepper, lettuce, and tomato. With the exception of acetamiprid, Þeld trial doses predicted from laboratory bioassay translated to effective Þeld efÞcacy. All products controlled F. occidentalis at the rates trialed and so have potential to augment current chemical controls. Increasing mortality correlated with increasing acetamiprid concentration in a greenhouse lettuce trial, suggesting that the higher trial rate (1.0 g [AI]/liter) may be required in some lettuce crops. The lower than registered (0.01 g [AI]/liter) rate of spinosad also signiÞcantly reduced F. occidentalis numbers and is a viable control option that may be useful in speciÞc integrated pest management programs. The implications of introducing neonicotinoids into existing insecticide resistance management strategies for F. occidentalis are discussed.

Journal of Economic Entomology, 2010

The life-stage variations in insecticide resistance of western ßower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), to selective insecticides (acrinathrin, formetanate, and methiocarb) were studied using resistant laboratory strains. In each strain, the second-instar larva was less susceptible to the insecticides tested than the adults. The lower the resistance level of the adults, the higher the difference between larva and adult susceptibility: 32-fold to methiocarb, 15.4-fold to formetanate, and 180-fold to acrinathrin in the reference strain. In laboratory-selected resistant strains, these differences were much lower: 5.8-fold to methiocarb, 4.8-fold to formetanate, and 2.0-fold to acrinathrin. In selected strains, higher resistance levels for each insecticide were found, both for larvae and adults, compared with the reference strain. These results show that after insecticide resistance selection in adults, the resistance is carried over to the larvae, but at lower levels.

2012

The western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae), is a most important pest of vegetable, fruit and ornamental crops around the world. The presence of this pest in strawberry fields has been associated with undesirable bronzing of the fruit. Experiments were conducted to assess the efficiency of four plant extract for control F. occidentalis on the strawberry in greenhouse conditions. Taguchi's design of experiments method has been used for to plan a minimum number of experiments and optimization to control of F. occidentalis. Four factors, which influence the control thrips, were chosen. These factors are type of pesticide (neem extract, coconut soap, tobacco extract and garlic-onion-pepper extract), dosage (recommended and twice dose), droplet size (250 µm and 1000 µm) and application value of pesticide (60 cc and 90 cc per vase). Orthogonal array L8 was used with three replicates. In order to determine the optimum levels of the control factors precisely, analysis of variance was performed. After optimization, the results showed that application value was the most effective factor. The optimum condition for control of F. occidentalis was found to be garlic-onion-pepper extract in twice of recommended dosage (Grind 20 g of garlic, 30 g of onions and 7 g pepper) with droplet size 1000 µm, and 90 cc of pesticide per vase for application value. This study is warranted to determine suitability of garlic-onion-pepper extract, as botanical insecticide, for inclusion in F. occidentalis integrated pest management programs.

Florida Entomologist, 2009

Feeding by the western flower thrips, Frankliniella occidentalis (Pergande), causes damage to the fruits of vegetables, and the species is the key vector of Tomato spotted wilt virus. Frankliniella tritici (Fitch) and Frankliniella bispinosa (Morgan) are not pests of fruiting vegetables. Both species compete with F. occidentalis. Effective management of F. occidentalis in pepper integrates conservation of natural populations of the predator, Orius insidiosus (Say), with the use of reduced-risk insecticides such as spinetoram for the control of western flower thrips and other pests. Naturally occurring O. insidiosus are very effective predators and their effectiveness is predictable based on the number of the predator relative to the number of thrips prey. Populations of F. occidentalis resurge when natural enemies and competing thrips are killed. Some insecticides especially pyrethroids have beneficial effects on the development and reproduction of F. occidentalis. The predator O. insidiosus does not prefer tomato, and numbers remain too low in fields to suppress thrips. Tomato growers primarily rely on the use of ultraviolet reflective mulch combined, if needed, with the use of effective insecticides. Additional management efforts are needed in the future to manage F. occidentalis and other difficult pests in space and time. Management of the pepper weevil (Anthonomus eugenii Cano) is proving a challenge to pepper growers in central and southern Florida trying at the same time to manage F. occidentalis. Growers need to emphasize sanitation and other cultural tactics over the use of broad-spectrum insecticides that kill O. insidiosus and induce F. occidentalis in other ways. The identification of thrips in scouting programs also is critical as the use of broad-spectrum insecticides against populations of the non-pest flower thrips is inducing F. occidentalis to pest status.

2003