Lepidopterous pests against

Flubendiamide is a promising new insecticide which is particularly active against lepidopteran pest species and is currently being co-developed by Nihon Nohyaku and Bayer CropScience. It is the first member ofa new chemical class of insecticides named phthalic acid diamides (Figure 5) to be developed. It has been shown to be extremely potent against lepidopterous pests including those resistant... 

Besides its main application against the sucking pest complex in Asian, Australian and Latin American cotton [15, 63-65], diafenthiuron has important specific additional uses against lepidopterous pests in brassicas in southeast Asia and the Far East. Specifically, good activity against susceptible and resistant strains of dia-mondback moth, the lesser armyworm, the small white butterfly and Spodoptera litura at rates ranging from 30-60 g-a.i. 100-L have been recorded [15, 66-69]. 

Pyridalyl Discovery, Insecticidal Activity, and Mode of Action 11115 Table 30.3.3 Insecticidal activity of pyridalyl against lepidopterous pests. 

Flubendiamide showed broad-spectrum activity against all lepidopterous pests, but is inactive against other insect species such as Coleoptera, Hemiptera and Acarina. It provides very high activity against all important lepidopterous insect pests shown in Table 31.1. 

Pyridalyl controls a wide variety of lepidopterous pest strains such as the diamondback moth (Plutella xylostella) which is resistant to various existing insecticides (8). This insecticide is also effective against thysanopterous pests. Moreover, it does not exert an adverse effect on various beneficial arthropods such as natural predator insects (e.g., Oristar-A ) and honeybees. Therefore, this novel insecticide is expected to be a usefiil material for controlling lepidopterous and thysanopterous pests in IPM and insecticide resistant management programs. 

Table 5. Insecticidal Activity of Pyridalyl against Lepidopterous Pests...

Pyridalyl resulted from a major synthetic program based on a series of lead conq)ounds and has proven to be very active against the larvae of some inq>ortant pests of cotton and vegetable crops. Pyridalyl also controls insecticide-resistant strains of lepidopterous pests as well as susceptible strains. It produces unique insecticidal symptoms so t it may have a different mode of action from any other existing insecticides. Pyridalyl is safer to mammals and various beneficial arthropods so that it Avill provide an mq)ortant tool in IPM and insecticide resistant management programs. Pyridalyl will become a safer chemical, and certainly contribute to establishment of sustainable chemistry. 

Thiodicarb is active against lepidopterous, coleopterous, hemipterous, and dipterous pests in soybeans, broccoli, cabbage, cauliflower, leafy vegetables, and cotton. Its oral LD50 in rats is 66 mg/kg. 

Tebufenozide is effective against lepidopterous insects. Halofenozide is used for control of grubs and other soilborne turf pests. Methoxy fenozide is used for control of a broad range of lepidopterous larvae. Chromafenozide is used for control of lepidopterous larvae. 

Table II shows the insecticidal activity of flubendiamide against major insect and acarina species. Flubendiamide provided high activity on all lepidopterous insect pests, and its ECjq values were between 0.004 and 0.58 mg a.i./L. However, flubendiamide did not show activity against other insect species. Thus, the insecticidal spectrum of flubendiamide is expected to be broad among lepidoptera pests in agriculture. Against the resistant strain of diamondback moth, flubendiamide provided the same level of activity as against the susceptible strain. This result indicates that flubendiamide will be useful for insecticide resistance management (IRM) programs.

Flubendiamide represents a novel class of insecticide having a unique chemical structure, and provides a new mode of action, which acts as a RyR modulator. This activity is highly selective to insect RyR, and no cross-resistance to existing insecticides is observed. Flubendiamide will also be very suitable for Insecticide Resistant Management. Furthermore, flubendiamide shows a broad insecticidal spectrum against lepidopterous insect pests, excellent efficacy in field evaluations, and excellent safety against various beneficial arthropods and natural enemies. It will be suitable for 1PM programs. 

One effect of these chemical modifications is that DE-175 is intrinsically more active against pest insect species than spinosad. For example, in a laboratory bioassay of topical toxicity to beet armyworm Spodoptera exigua) larvae, DE-175 is 48X more active than spinosad (Table 29.3.3). Similar results are observed in a bioassay of ingestion activity, where DE-175 is 58 x more active on beet army-worm than spinosad. Improved potency of DE-175 is also observed against other lepidopterous insects, though to a lesser degree (Table 29.3.3). 

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