Effectiveness in the field of Bt rice lines against target pests under various cultural regimes

China has a long history of rice cultivation, incorporating several cultural practices known to influence damage by insect pests. Transgenic Bt rice expresses lepidopteran‐specific insecticidal proteins that primarily target lepidopteran insect pests. However, the effectiveness of Bt rice against target insect pests under different cultural regimes has not been evaluated. In this study, the effectiveness of Bt rice lines against rice leaffolder, Cnaphalocrocis medinalis (Guenée) (Lepidoptera: Pyralidae), and striped stem borer, Chilo suppressalis Walker (Lepidoptera: Crambidae), was evaluated under various transplanting densities, crop establishment methods, and planting times. The results showed that Bt rice lines (T2A‐1 and T1C‐19, containing Cry2A and Cry1C, respectively) could prevent damage by these target pests under a range of cultural practices. Injury by C. medinalis or C. suppressalis on rice did not differ with the rice lines under various transplanting densities. Direct‐seeded non‐Bt rice MH63 suffered heavier injury by C. medinalis and C. suppressalis than it did with transplanting, whereas injury to the two Bt rice lines did not differ with planting methods. Planting time significantly affected injury by C. medinalis or C. suppressalis on non‐Bt rice, whereas injury to Bt rice lines did not differ with planting time. These results suggest that transplanting density, planting method, and planting time did not significantly affect the resistance of two Bt rice lines, due to their high insecticidal activity against target insects.     

Design,synthesis and insecticidal evaluation of aryloxy dihalopropene derivatives

Plutella xylostella (P. xylostella) is a highly migratory, cosmopolitan species and one of the most important pest of cruciferous crops worldwide. Pyridalyl as a novel class of insecticides has good efficacy against P. xylostella. On the basis of the commercial insecticide pyridalyl, a series of new aryloxy dihalopropene derivatives were designed and synthesized by using Intermediate Derivatization Methods. Their chemical structures were confirmed by ¹H NMR, high-resolution mass spectrum (HRMS), and single-crystal X-ray diffraction analysis. The insecticidal activities of the new compounds against P. xylostella were evaluated. The results of bioassays indicated that most of the compounds showed moderate to high activities at the tested concentration, especially compounds 10e and 10g displayed more than 75% insecticidal activity against P. xylostella at 6.25 mg/L, while pyridalyl showed 50% insecticidal activity at the same concentration. The field trials result of the insecticidal activities showed that compound 10e as a 10% emulsifiable concentrate (EC) was effective in the control of P. xylostella at 75–150 g a.i./ha, and the mortality of P. xylostella for treatment with compound 10e at 75 g a.i./ha was equivalent to pyridalyl at 105 g a.i./ha.     

Evaluation of pesticides against major pests of jute (Corchorus olitorius L.) in West Bengal,India

Among the pesticides evaluated against the jute pests under field conditions, endosulfan 35 EC at 350 g a.i./ha was found to be the most effective insecticide for controlling semilooper, Bihar hairy caterpillar and myllocerus weevil. Endosulfan and fenpropathrin provided good control of yellow mite as well. Even, endosulfan-treated plots gave maximum fibre and stick yield with greater benefit–cost ratio (BCR) over others. Next to endosulfan and chlorpyriphos, neemazal (azadirachtin 50,000 ppm) are useful and safer options against semilooper, Bihar having caterpillar, myllocerus and yellow mite. Methoxyfenocide 10 EC at 200g a.i./ha provided good control (70.60%) of S. obliqua even after 14 days of spraying, but it was not effective against other pests of jute. Further, almost similar efficacy of neemazal and chlorpyriphos was found against the pest complex of jute and based on BCR, neemazal could be an alternative choice over chlorpyriphos.     

Control of Heterodera carotae,Ditylenchus dipsaci,and Meloidogyne javanica with Fumigant and Nonfumigant Nematicides

Five field trials were conducted in Italy in 1983 and 1984 to test the efficacy of isazofos and benfuracarb in controlling Heterodera carotae on carrot, Ditylenchus dipsaci on onion, and Meloidogyne javanica on tomato. Methyl isothiocyanate (MIT) was tested against H. carotae and M. javanica. Single (10 kg a.i./ha) and split (5 + 5 kg a.i./ha) applications of isazofos gave yield increases of carrot and onion similar to those obtained with DD (300 liters/ha) and aldicarb (10 kg a.i./ha). Population densities of H. carotae in carrot roots at harvest and of M. javanica in tomato roots 2 months after transplanting were also suppressed by isazofos. Benfuracarb (10 kg a.i./ha increased onion yields in a field infested with D. dipsaci, but it was not effective against H. carotae or M. javanica. The efficacy of MIT at 400 and 600 liters/ha was similar to that of MIT + DD (Di-Trapex) at 300 liters/ha. Both nematicides inhibited hatch of H. carotae eggs and decreased the soil population density of M. javanica.     

The efficacy of high and low volume spray applications of Mimic® (tebufenozide) for managing autumn gum moth larvae Mnesampela privata (Lepidoptera: Geometridae) in eucalypt plantations

Abstract 1 The autumn gum moth Mnesampela privata (Guenée) (Lepidoptera: Geometridae, Ennominae) is a native moth that can outbreak, resulting in significant defoliation of plantation eucalypts in southern Australia. 2 Laboratory trials tested M. privata larvae for their dose–response to the ecdysone agonist, Mimic® 700 WP (a.i. 700 g/kg tebufenozide); ground and aerial field trials also tested its efficacy in eucalypt plantations. 3 The laboratory trials showed that there was no significant difference in mortality between larvae treated with 172 g Mimic® (120 g a.i)/ha and those sprayed with doses ranging from 86 to 3340 g Mimic®/ha. 4 Laboratory and field trials demonstrated that second instars were the most susceptible, with the most rapid response. However, second to fourth instars all reached 100% and fifth instars 90% mortality 3 weeks after aerial spraying at 120 g a.i./ha. 5 Aerial spraying an Eucalyptus globulus plantation with 120 g a.i. Mimic® at 20 L/ha caused 95% mortality of instars two to five, and 100% for instars two to four within 3 weeks after spraying. 6 Ground spraying to run‐off with 120 g a.i. Mimic®/ha reduced defoliation of E. grandis from between 67% to 80% for unsprayed trees to 0% defoliation for sprayed trees. 7 The window for effective management of M. privata larvae is 3–5 weeks, during first to third instar development. 8 Replacement of broad‐spectrum insecticides with the more target‐specific Mimic® should increase the biodiversity of plantations and therefore would be more environmentally friendly.     

Rapid microsatellite marker isolation for the Pink Stem Borer,Sesamia inferens (Lepidopetera: Noctuidae), through 454 GS-FLX Titanium pyrosequencing of enriched DNA libraries and cross amplification in related taxa

Next-generation Roche 454 pyrosequencing was used to rapidly identify polymorphic microsatellites from enriched DNA libraries for the pink stem borer, Sesamia inferens (Walker). A total of 1,459 simple sequence repeats (SSRs) were isolated from the microsatellite-enriched library using 454 sequencing. Thirty-nine microsatellite markers were selected to synthesize for further optimization, and 12 loci exhibited reliable amplification of a single product of expected size. The forward primer of 12 primer pairs was end labeled with a fluorescent dye. All of the 12 microsatellite loci were polymorphic, with 5–13 alleles per locus and observed heterozygosities ranging from 0.097 to 0.957. Here, we also tested these 12 SSRs for cross-species amplification in Chilo suppressalis (Walker), Tryporyza incertulas (Walker) and Cnaphalocrocis medinalis (Guenée). These polymorphic markers will be a valuable tool for analyses of population connectivity and genetic structure in this rice pest.     

Barrier spraying to control the malaria vector Anopheles albimanus: laboratory and field evaluation in the Dominican Republic

Abstract. To develop a new strategy for control of exophilic/exophagic malaria vectors which rest on peridomestic foliage, Anopheles albimanus was used for laboratory bioassays of mosquito adulticides applied to various vegetation types. Of the three classes of insecticide tested, the pyrethroid (permethrin at 112 g/ha) showed greater foliar persistence than either the carbamate (bendiocarb at 340g/ha) or the organophosphorus compound (malathion at 277g/ha). Field evaluation of barrier spraying against An.albimanus was evaluated in rural villages of southwest Dominican Republic during 1989. The pyrethroid deltamethrin was sprayed aerially for ultra-low volume application at treatment rates of 17-19ga.i./ha in a radius of 500m around two villages. An.albimanus were monitored by light-traps and human bait collections at both treated villages, compared with two similar untreated villages, up to 9 nights post-treatment. Densities of female An.albimanus were significantly reduced in the sprayed villages for at least 8 or 9 nights. Further evaluation of barrier spraying is recommended to determine optimal pyrethroid formulations and applications rates, their impact on non-target fauna and efficacy against malaria transmission.     

Control of Globodera rostochiensis in Relation to Method of Applying Nematodes

Soaking potato tuber pieces for 15 min in 8,000 μg/ml of oxamyl just before planting reduced the number of Globodera rostochiensis cysts that developed on potato roots, but this treatment was phytotoxic. Five foliar applications of 1.12 kg a.i./ha of oxamyl or carbofuran at 10-day intervals beginning when 90% of the plants had emerged suppressed increase in G. rostochiensis densities. Similar foliar applications of phenamiphos were ineffective in controlling G. rostochiensis. Soil applications (in the row at planting) of aldicarb, carbofuran, phenamiphos, ethoprop, and oxamyl at 5.6 kg a.i./ha reduced the numbers of white females that developed on potato roots, but only those treatments involving aldicarb and oxamyl suppressed G. rostochiensis population increase. Combined soil and foliar treatments did not provide any advantage over soil treatment alone, as soil applications of 5.6 kg a.i./ha alone were equal to, or better than, combined soil (3.4 kg a.i./ha) and foliar (2.2 kg a.i./ha) applications in controlling G. rostochiensis.     

The interaction of protectants with EPTC on field bean, and tri-allate on wheat

Protectants (antidotes) were tested for their potential to protect field beans (Vicia faba L.) from EPTC damage, or wheat (Triticum aestivum L.) from triallate damage. For both crops there was considerable variation in the degree of protection shown from similar treatments in different experiments. For field bean, a seed treatment of 1,8-naphthalic anhydride (NA) at 5 mg/g seed gave some protection from EPTC applied pre-planting at 4–8 kg a.i./ha but not in all experiments. NA also caused marked chlorosis of the foliage. N, N-diallyl-2, 2-dichloroacetamide (R25788) at 20 mg/g seed severely damaged field bean in the absence of herbicide but 5 mg/g gave comparable protection from EPTC to that given by NA and did not cause chlorosis. Mixing R25788 with EPTC in the spray tank gave reduced protection. In a single experiment R4115 (chemistry undisclosed) gave some protection against EPTC damage. For wheat, a seed treatment of 5–20 mg/g NA sometimes countered damage from tri-allate applied pre-planting at 1 kg a.i./ha but not generally from higher doses. R25788 sometimes protected from weight loss due to tri-allate at 1 kg a.i./ha but not from damage symptoms, whereas R4115 at 20 mg/g seed alleviated these symptoms but did not prevent weight loss. R25788 at 4 kg a.i./ha mixed in the spray tank with the herbicide partially reduced weight loss and damage symptoms from a dose of 2 kg a.i./ha. Some treatments of R29148 gave complete protection from tri-allate at 1 kg a.i./ha. The results are discussed in the context of the full data from the two series of experiments.     

Sex pheromone components of the rice leaffolder,Cnaphalocrocis medinalis (Lepidoptera: Crambidae), in Indonesia

Field tests of three synthetic sex pheromone blends (Japanese blend: Z11–18:Ald (55 μg), Z13–18:Ald (500 μg), Z11–18:OH (120 μg) and Z13–18:OH (180 μg), Indian blend: Z11–16:Ac (50 μg) and Z13–18:Ac (500 μg) and Philippine blend: Z11–16:Ac (500 μg) and Z13–18:Ac (10 μg) based on geographic variations in sex pheromones) of the rice leaffolder moth, Cnaphalocrocis medinalis Guenée (Lepidoptera: Crambidae), were conducted at Yogyakarta (Java), and at Sempidi and Penatih (Bali), Indonesia. Only the Japanese blend attracted significant numbers of male C. medinalis, while neither the Indian nor the Philippine blend showed any attractiveness to the males. In the GC–MS analysis of a crude extract from pheromone glands of female C. medinalis collected at Sanur, Bali. Indonesia, Z11–18:Ald, Z13–18:Ald, Z11–18:OH and Z13–18:OH were detected at a ratio of 10:100:26:37, and the total amount was approximately 0.8 ng/female. Neither Z11–16:Ac nor Z13–18:Ac were detected. These results suggest that C. medinalis that respond to the Japanese blend are widely distributed from Eastern Asia through Southeast Asia.     

The influence of climatic conditions around the time of spraying isoproturon on the subsequent injury to barley

Winter barley cv. Igri was grown in pots, either outside under cover, in a glasshouse or under controlled conditions and treated post-emergence with isoproturon. There was a linear relationship between the subsequent weight of plants treated with 2.5 kg a.i./ha and either evaporation from a water surface between 2–7 days post spraying or cumulative temperature between sowing and spraying. The relationship between subsequent weight of plants treated to the foliage only with 5 kg a.i./ha and cumulative temperature between sowing and spraying varied between years 1984–86. The post spraying environment had the major influence on subsequent activity of isoproturon at 2.5 kg a.i./ha applied overall to barley under controlled conditions. There was a greater reduction in CO₂ exchange in plants grown after treatment under high compared to low relative humidity. When isoproturon at 5 kg a.i./ha was applied to barley plants with wet foliage, plants were slower to recover their initial rate of photosynthesis when kept wet for 24 h as compared with 11 h or when allowed to dry after treatment. Photosynthesis was decreased to a lesser extent under the same post spray conditions by 2.5 than by 5 kg a.i./ha and reduction was greater and recovery of photosynthesis slower in plants grown inside compared to outside.     

Herbivore-induced rice resistance against rice blast mediated by salicylic acid

In agro-ecosystems,plants are important mediators of interactions between their associated herbivorous insects and microbes,and any change in plants induced by one species may lead to cascading effects on interactions with other species.Often,such effects are regulated by phytohormones such as jasmonic acid(JA)and salicylic acid(SA).Here,we investigated the tripartite interactions among rice plants,three insect herbivores(Chilo suppressalis,Cnaphalocrocis medinalis or Nilapai-vata lugens),and the causal agent of rice blast disease,the fungus Magnaporthe oryzae.We found that pre-infestation of rice by C.suppressalis or N.lugens but not by C.medinalis conferred resistance to M.oryzae.For C.suppressalis and N.lugens,insect infestation without fungal inoculation induced the accumulation of both JA and SA in rice leaves.In contrast,infestation by C.medinalis increased JA levels but reduced SA levels.The exogenous application of SA but not of JA conferred resistance against M.oryzae.These results suggest that preinfestation by C suppressalis or N.lugens conferred resistance against M.oryzae by increasing SA accumulation.These findings enhance our understanding of the interactions among rice plant,insects and pathogens,and provide valuable information for developing an ecologically sound strategy for controlling rice blast.     

Field evaluation of 4-n-butyl-1,2,4-triazole for the control of leaf rust of triticale*

Severe epidemics of triticale leaf rust were controlled by a single treatment with 4-n-butyl-1,2,4-triazole (triazbutyl) as a foliar spray or as broadcast application on soil followed by irrigation. A single foliar spray of triazbutyl at 0.5 litre a.i./ha approached the control obtained by 1.0 litre a.i./ha. Effective control was obtained by spraying 10 days before or 10 days after the rust appearance but later spray applications were less effective.     

Control of Ditylenchus dipsaci in Infected Garlic Seed Cloves by Nonfumigant Nematicides

Different rates of granular formulations ofaldicarb, carbofuran, ethoprop, fensulfothion, and phenamiphos were applied directly onto garlic seed cloves in the seed furrow in sandy clay loam, clay loam, and loam soils at planting to assess efficacy for control of Ditylenchus dipsaci in infected seed cloves. All treatments were compared to hotwater-formalin clove dip disinfection treatment and to nontreated infected controls. Aldicarb and phenamiphos at 2.52 and 5.04 kg a.i./ ha, but not at lower rates, effectively suppressed infection by D. dipsaci and increased yields. Although both nematicides slightly slowed the rate of plant emergence, normal stands were established. Trace levels of infection occurred in all treatments, including the hotwater-formalin dip. Carbofuran at 5.04 kg a.i./ha controlled the nematode but was phytotoxic. Ethoprop was phytotoxic. Fensulfothion did not control D. dipsaci even at the highest application rate, 8.90 kg a.i./ha. Single and multiple applications of oxamyl at 1.12-8.96 kg a.i./ha, applied as a surface spray or in furrow irrigation water, slowed the early progression of disease symptoms but failed to provide season-long nematode control.     

Saxitoxin monitoring in three species of Florida puffer fish

Beginning in April 2002, three species of Florida puffer fish from around the state of Florida, USA were monitored for the presence of saxitoxin (STX). In total, 873 southern (Sphoeroides nephelus), 171 checkered (S. testudineus), and 53 bandtail (S. spengleri) puffer fish were collected between 2002 and 2006 from eight regions: Jacksonville, the Indian River Lagoon, Tequesta, the Florida Keys, Charlotte Harbor, Tampa Bay, Cedar Key, and Apalachicola. Emphasis was placed on collecting specimens from the Indian River Lagoon (IRL), where recreational harvesting of puffer fish led to 28 cases of saxitoxin puffer fish poisoning (SPFP) between January 2002 and May 2004. Southern puffer fish from the northern IRL routinely contained the highest concentrations of STX, with average levels in the skin of 1787 μg STXequiv./100 g tissue. Elevated concentrations were also found in the muscle (1102 μg STXequiv./100 g), gut contents (539 μg STXequiv./100 g), gonads (654 μg STXequiv./100 g), and liver (214 μg STXequiv./100 g). Lower, yet significant (above the action limit of 80 μg STXequiv./100 g tissue), concentrations of STX were also detected in the skin (599 μg STXequiv./100 g), muscle (233 μg STXequiv./100 g), gut contents (197 μg STXequiv./100 g), and gonads (239 μg STXequiv./100 g) of southern puffer fish from Tequesta in the southern IRL, as well as in the gonads (122 μg STXequiv./100 g) of Jacksonville southern puffer fish and the skin (265 μg STXequiv./100 g) of Tampa Bay southern puffer fish. STX concentrations above the action limit were also found in the skin of bandtail puffer fish from the IRL (620 μg STXequiv./100 g), Tequesta (374 μg STXequiv./100 g), and the Florida Keys (230 μg STXequiv./100 g). Checkered puffer fish collected from the IRL, Tequesta, and the Florida Keys on average were nontoxic, containing STX levels below the action limit in all tissues.     

The effect of seed and stem base spray treatment with iprodione on white rot disease (Sclerotium cepivorum) in autumn-sown salad onions

Iprodione applied to seed at 250 g a.i./kg controlled white rot in autumn-sown salad onions until July the following year, and reduced losses during the winter caused by Botrytis spp. At 25–150 g a.i./kg seed, iprodione controlled autumn and spring infections but it was less effective later in the summer. Treatment of autumn-sown onions at 50 g a.i./kg seed followed in March by a single stem base spray at 0.031 g a.i./m row (total rate c. 2.4 kg a.i./ha) gave complete control; seed treatment at 25 g a.i./kg followed by a stem base spray at 0.125 g a.i./m row (c. 4.5 kg a.i./ha) was equally effective. Four stem base sprays of iprodione at 0.075 g a.i./m row/spray (9 kg a.i./ha) applied in spring to plants raised from untreated seed, controlled spring and summer infections but yields were low because of losses caused by infection in the previous autumn. A single stem base spray of iprodione at 0.125 g a.i./m row applied in spring to plants raised from thiophanate-methyl treated seed at 125 g a.i./kg gave complete control and high yields.     

Efficacy of Aldicarb to Rotylenchulus reniformis and Biodegradation in Cotton Field Soils

The microbial degradation of aldicarb was examined in the greenhouse using soil from four cotton fields with a history of aldicarb use. The addition of aldicarb at 0.59 kg a.i./ha to natural soil increased Rotylenchulus reniformis numbers 6.6% in one soil and decreased R. reniformis numbers only 25.8% in another soil as compared to the corresponding natural soil without aldicarb. The use of increasing rates of aldicarb did not increase the efficacy of aldicarb in these soils. Rotylenchulus reniformis numbers were reduced 39.8, 22.6, and 6.8%, and increased 5.7% for aldicarb applied at 0.29, 0.59, 0.85, and 1.19 kg a.i./ha, respectively, in one natural soil. In another natural soil, R. reniformis numbers were reduced 42.5 and 21.9% for aldicarb applied at 0.29 and 1.19 kg a.i./ha, respectively, but increased 19.1 and 10.6% for aldicarb applied at 0.59 and 0.85 kg a.i./ha, respectively. Autoclaving the soils restored aldicarb toxicity in both soils, and R. reniformis numbers were reduced 96 and 99%, respectively, as compared to autoclaved soil without aldicarb. Bacterial populations were greater in the natural soils where aldicarb did not reduce R. reniformis numbers relative to the same soils that were autoclaved. However, no bacterial species was consistently associated with aldicarb degradation.     

Water-soluble granules containing <Emphasis Type="Italic">Bacillus megaterium</Emphasis> for biological control of rice sheath blight: formulation,bacterial viability and efficacy testing

Endospores of B. megaterium were formulated in granule formulations with sodium alginate, lactose and polyvinylpyrrolidone (PVP K-30) by the wet granulation technique. The granule formulation exhibited good physical characteristics, such as high-water solubility and optimal viscosity, that would be suitable for spray application. The bacteria remained viable in the dry granule formulation at 10⁹ c.f.u./g after 24 months storage at room temperature. Under laboratory conditions, aqueous solutions of the formulation showed high activity against mycelial growth of R. solani (99.64 ± 0.14% mycelial inhibition). High viability of the bacterial antagonist on leaf sheath and leaf blade at day 7 after spraying with the formulation was observed (approximately 10⁶ c.f.u./g of plant). Application of an equivalent number of un-formulated endospores resulted in much loss of the bacterial endospores even 1 day after application. In a small pilot field study, an aqueous solution of the formulation (3%w/v) applied by spraying at days 1, 5 and 10 after pathogen inoculation of the rice plants was more effective in suppressing rice sheath blight disease than one application of a fungicide (Iprodione) at day 1. Additionally, rice plants sprayed with the aqueous solution of the granule formulation had higher panicle and whole kernel weights than those of fungicide-treated and control (untreated) plants.     

Effects of imazamethabenz on the main shoot growth and tillering of wild oat (Avena fatua L.)

Foliar application of imazamethabenz at sublethal doses of 100 and 200 g a.i./ha to wild oat plants at the two-leaf stage without tillers greatly inhibited the growth of the main shoot but increased tillering. The near cessation of sheath and the main stem elongation indicated that the major effect of imazamethabenz on the main shoot was inhibition of intercalary growth. Low doses of imazameth-abenz treatment resulted in more leaves (including leaf primordia) in the main stem but did not affect mature first and second leaves. Sublethal doses of imazamethabenz only briefly inhibited tiller growth. A later increase in tillering in treated plants resulted from the stimulated resumed growth of tillers and the increased initiation of tiller buds. Such enhanced tillering mainly resulted from the release of apical dominance due to the inhibition or cessation of the main stem growth with imazamethabenz treatment. Both doses of imazamethabenz (100 and 200 g a.i./ha) significantly reduced the biomass of shoots and roots, but increased the ratio of roots/ shoots dry weight.     

Use of Avermectins for the Control of Meloidogyne incognita on tomatoes

The efficacy of avermectins B₁ and B₂ for control of Meloidogyne incognita on tomato was studied in pots and field plots for two seasons. Avermectins were applied as granules and liquid in furrows or by low pressure drip irrigation systems, at rates ranging from 0.093 to 0.34 kg a.i./ha, as single or multiple applications. Levels of control comparable to those obtained by oxamyl and aldicarb at 3.36 kg a.i./ha were achieved by the avermectin with only 1/10 the volume of chemicals applied to the environment. Avermectin protection of the roots remained constant throughout the first 5 weeks giving slightly longer protection than oxamyl or aldicarb.