Dose-Response Tests with Neem Azal-T Against the Cabbage Moth, 1995 (original) (raw)
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Journal of Agriculture of The University of Puerto Rico, 1969
Three field trials with cabbage var. Market Prize were established at the Isabela Substation, AES-UPR, to evaluate the susceptibility of Plutelfa xylostella to various insecticides. Dosages recommended by the manufacturer were used for the first two applications in the first trial, and some double dosages were included in an attempt to get at least a 90% control of the larvae population. For the other two trials, recommended dosages and the effective higher dosages from the first trial were compared. Significant differences were obtained with methamidophos {2.34 L/ha), permethrin (0.234 and 0.468 l/ha), and fenvalerate (0.35 L/ha) for controlling the larvae. Control figures for those four treatments were 97.8, 100, 100, and 99.9%, respectively. Methamidophos, acephate, and naled controlled over 90% of the larvae only with double the recommended rates. Chlorpyrifos at 1.17 L/ha was ineffective, but at its higher rate controlled 80 to 90% of the larvae. Diazinon, methomyl, dimethoate, and endosulfan even at their highest rates were ineffective for controlling the larvae. The number of larvae increased after each application of these insecticides. The greatest numbers of marketable heads were obtained from plots treated with permethrin, fenvalerate, and methamidophos at the highest rate for each, RESUMEN
Journal of Agricultural Science and Technology A, 2016
The diamondback moth, Plutella xylostella L., has developed resistance to most insecticides used for its management. Suggested alternatives to forestall this process include biorational insecticides in mixtures with low-risk insecticides. The aim of this study was to select an insecticide or insecticide mixture that could be adopted by small-scale growers for diamondback moth management. The effectiveness of four insecticide mixtures, i.e., Agroneem ® Plus (neem-derived), Spinosad (microbial origin), thiamethoxam (neonicotinoid) and a homemade methanol Jalapeño pepper extract, in laboratory bioassays was evaluated. Binary mixtures were tested against single products at manufacturer's label rates. These were applied to collard greens using the leaf dip method and fed to the newly molted 2nd or 3rd instar larvae. Mixtures were evaluated for efficacy based on larval mortality and consumption of leaf discs. The results showed interactions between Jalapeño pepper extract and Spinosad and between the neem-derived Agroneem ® Plus and thiamethoxam at some of the tested concentrations. Mixtures with at any amount of Spinosad killed all larvae. The neem-based product gave inconsistent results in some treatments; in some case, increased leaf damage did not result in commensurate larval mortalities. The reported resistance of diamondback moth larvae to Spinosad was not observed during this study, neither with Spinosad alone nor in mixtures.
Journal of Applied Entomology, 2003
Behavioural responses of female Diadegma mollipla to volatiles from cabbage plants and host-infested [Plutella xylostella (L.)] cabbage plants sprayed with two neem insecticide formulations were investigated in a Y-tube olfactometer. Parasitoids were significantly more attracted to volatiles from cabbage and host-infested cabbage sprayed with the powder formulation than to clean air. In contrast, parasitoid response to volatiles from cabbage and hostinfested cabbage sprayed with the oil formulation was not significantly different from clean air. In choice tests between infested plants sprayed with water (control) or the powder formulation, parasitoids showed no preference for volatiles from either of the treatments. In similar tests with the oil formulation, parasitoids showed a preference for volatiles from control plants over plants sprayed with the oil formulation. In host acceptance and suitability tests, parasitism rates in the neem-and water-sprayed hosts were, with one exception, not significantly different. However, the neemsprayed larvae died earlier than control larvae and were therefore not able to support parasitoid development. The implication of these findings for the combined use of neem insecticides and parasitoids in the management of P. xylostella is discussed.
Journal of Pest Science, 2006
A diet-incorporation larval bioassay was used to evaluate the response of the leafroller Pandemis heparana (Denis and Schiffermu¨ller) to seven insecticides: tebufenozide (Mimic 23% a.i., Bayer), methoxyfenozide (Prodigy 23% a.i., Bayer), flufenoxuron (Cascade 50 DC 4.7% a.i., BASF), lufenuron (Match 5.32% a.i., Syngenta), indoxacarb (Steward WG 30% a.i., Du Pont), abamectine (Vertimec EC 1.9% a.i., Syngenta) and spinosad (Laser 44.2% a.i., Dow Agro Science). Both neonate and 12-day-old (third to fourth instar) larvae were used in the bioassay. The obtained efficacy baselines were compared with the response of the pest exposed to leaves treated with the same insecticides. The persistence of field-aged leaf residues of the seven insecticides was bioassayed on neonate larvae. Given the obtained LC 50 values in the diet-incorporation bioassays larval age was not always a significant factor affecting the response of P. heparana larvae. Differences in LC 50 values between neonate and 12-dayold larvae were not statistically significant for abamectine, tebufenozide and methoxyfenozide. Young larvae seemed to be more susceptible than older larvae to spinosad, indoxacarb and lufenuron, while flufenoxuron was more effective against 12-day-old than neonate larvae. When the larvae were exposed to the insecticides on treated leaves, all the tested compounds were less effective on older larvae than on neonates. When applied at the recommended field rates, all seven insecticides can be considered highly effective against both neonate and 12-day-old larvae of P. heparana because their security index (SI = recommended field rate/LC 90) always exceeded the threshold value of 1. The high persistence of insect growth inhibitors (IGIs) and moulting accelerating compounds (MACs) in the field compensates for their relatively low SI values. For this reason and given their activity against Cydia pomonella, IGIs and MACs are the most interesting insecticides for spring treatments for the combined control of both species, P. heparana and C. pomonella.
Toxicity of insecticides to diamondback mothPlutella xylostella(L)
New Zealand Journal of Experimental Agriculture, 1983
Dosage-mortality relationships for permethrin, fenvalerate, methamidophos, and carbaryl against diamondback moth, Plutella xylostella (L.) were determined under laboratory conditions by caging larvae on broccoli leaf discs, which had been sprayed under a Potter tower, and by spraying adults directly. LC, values were determined at 48 h. The toxicity of permethrin and fenvalerate to third instar larvae was 10 to 160 times more than methamidophos and carbaryl respectively. Permethrin and fenvalerate were 2 to 260 times more toxic than methamidophos and carbaryl respectively. The effect of post-treatment temperatures of 15°C and 25°C on the toxicity of the 4 insecticides to larvae was also determined. A marked increase in toxicity of pyrethroids, and decrease in toxicity of carbaryl, was observed at 15OC.
Environmental Toxicology and Pharmacology, 2016
The wheat head armyworm, Dargida (previously Faronta) diffusa (Walker) (Lepidoptera: Noctuidae), is widely distributed in North American grasslands and is most common on the Great Plains, where it is often a serious pest of corn and cereal crops. Six commercially available botanical or microbial insecticides used against D. diffusa were tested in the laboratory: Entrust ® WP (spinosad 80%), Mycotrol ® ESO (Beauveria bassiana GHA), Aza-Direct ® (azadirachtin), Met52 ® EC (Metarhizium brunneum F52), Xpectro ® OD (Beauveria bassiana GHA + pyrethrins), and Xpulse ® OD (Beauveria bassiana GHA + azadirachtin). Concentrations of 0.1, 0.5, 1.0 and 2.0 fold the lowest labelled rates of formulated products were tested for all products, while for Entrust WP additional concentrations of 0.001 and 0.01 fold the label rates were also assessed. Survival rates were determined from larval mortality at 1-9 days post treatment application. We found that among the tested chemicals, Entrust ® (spinosad) was the most effective, causing 83-100% mortality (0-17% survival rate) at day 3 across all concentrations. The others, in order of efficacy from most to least, were Xpectro ® (B. bassiana GHA + pyrethrins), Xpulse ® OD (B. bassiana GHA + azadirachtin), Aza-Direct ® (azadirachtin), Met52 ® EC (M. brunneum F52), and Mycotrol ® ESO (B. bassiana GHA). These products and entomopathogenic fungi caused 70-100% mortality (0-30% survivability) from days 7 to 9. The tested products and entomopathogenic fungi can be used in management of D. diffusa.
Acta agriculturae Slovenica
Using chemical pesticides has adverse effects on the environment and humans. Bacterial preparations may provide an alternative to chemical pesticides. The study aims to test different combinations of sublethal concentrations of bacterial and chemical preparations against cabbage moth larvae. During 2020-2022 different combinations of sublethal concentrations of bacterial (Lepidocide) and chemical (Arrivo, Voliam Flexi, Proclaim Fit) preparations were tested in laboratory and field conditions, against cabbage moth young larvae (stage I-II). The combinations of insecticides with bacterial and chemical sublethal concentrations show high biological efficiency against the cabbage moth larvae. No statistical difference was found between the efficiency indicators of the combined and standard chemical (Arrivo, Voliam Flexi, Proclaim Fit) options and the significance level was generally between 2.0 and 5.9 %, showing that the results of the scientific experiments are reliable.
Systemic effects of a neem insecticide on Liriomyza huidobrensis larvae
Phytoparasitica, 1997
In an effort to expand the spectrum of larvicides effective against the pea leafminer, Liriomyza huidobrensis (Blanchard), we studied the effects of a neem-based insecticide (Neemix-45) on the development of the leafminer under laboratory conditions. Bean plants were treated with a soil drench of 1, 5, 10 or 25 ppm azadirachtin or by dipping leaves in 1 or 15 ppm azadirachtin at various times before or during the development of the leafminer. Treating the plants with the neem insecticide before exposure to egg-laying adults had a greater effect on inhibiting the development of pupae and adult eclosion than treatment at the 1st-instar larval stage. The systemic effects from a soil drench had a greater adverse effect on pupation and adult eclosion than leaf dipping. Drenching plants with 1 ppm azadirachtin 24 h before exposure to adults had a greater effect (0% adult eclosion) than leaf dipping at the same time period and concentration (15.6% adult eclosion). Similar results were obtained when drenching plants infested with 1st-instar larvae with 1 ppm azadirachtin (11.7% eclosion) vs dipping leaves at the same time period and concentration (44.7% eclosion).