Thiacloprid

Imidacloprid (1) provides additional control of Cokopteran spp. (e.g., rice water and tobacco weevil, Colorado potato beetle, rice leaf beetle, wrreworms, grubs and other soil beetles) and Dipterans spp. (e.g., fruit fly, beet fly, bean and onion fly) and of selected micro-lepidopteran species (e.g., citrus, apple and potato leaf miner), ants Hymenoptera spp.), termites Isoptera spp.), cockroaches, grasshoppers and crickets Orthoptera spp.) [53]. 

Apart from the direct insecticidal activity of 1 it posses several sublethal side effects as well. The effects are sometimes dosage dependent and include repel-lency, reduction of cessation of feeding, reduction or cessation of reproductive activities, overall reduction of movement or activity, and increased susceptibility to biological control. The excellent anti-feeding effects of 1 results in less time for transmission and shorter xylem contact so that the number of infections per time units is reduced considerably. 

Furthermore, 1 is harmless to many beneficial organisms, like predacious mites and spiders independent of the application method employed. Therefore, 1 is a suitable product for I PM (Integrated Pest Management). 

The metabolism of 1 is strongly influenced by the method of application [54]. Depending on time and plant species 1 is degraded more or less completely, as comparative studies in many field crops have revealed [55]. 

In connection with the excellent biological performance and market acceptance of imidacloprid (1), a further, extensive research and development program led to the discovery and development of the five-membered neonicotinoid thiacloprid (9) (2000, Bayer CropScience) [56, 57], the second member of the CNI family. 

---

EC Decision on the view of the possible inclusion of thiacloprid, forchlorfenuron, thiamethoxam m... 

Neonicotinoids are potent broad-spectrum insecticides that exhibit contact, stomach and systemic activity. Acetamiprid, imidacloprid, nitenpyram, thiamethoxam and thiacloprid are representatives of the neonicotinoid insecticides (Figure 1). The mechanism of action is similar to that of nicotine, acting on the central nervous system causing irreversible blocking of postsynaptic nicotinic acetylcholine receptors (nAChR). Neonicotinoid insecticides are often categorized as antagonists of the... 

Neonicotinoids are generally polar, nonvolatile crystals with high water solubility. They are nonionized at environmentally relevant pH and are stable to heat and sunlight. Neonicotinoids are stable to acid hydrolysis. Except for thiacloprid, they are susceptible to alkaline hydrolysis. 

The definition of crop residues for thiamethoxam and thiacloprid includes the parent and its metabolite fV-(2-chlorothiazol-5-ylmethyl)-fV -methyl-A"-nitroguanidine (designated the guanidine compound) for thiamethoxam, and 3-(6-chloro-3-pyridylmethyl)-l,3-thiazolidin-2-ylideneaminocarboxamide (designated the amide compound) for thiacloprid (Figure 3). 

Amide compound of thiacloprid Guanidine compound of thiamethoxam Figure 3 Stmctures of metabolites of thiacloprid and thiamethoxam... 

Analyte Acetamiprid Imidacloprid Nitenpyram metabolite Thiacloprid metabolite Thiamethoxam metabolite Imidacloprid... 

The definition of water residue for the neonicotinoid insecticides except for niten-pyram and thiacloprid is the parent molecule. For nitenpytram and thiacloprid both the parent and its metabolites are determined. These metabolites are 2-[A-(6-chloro-3-pyridylmethyl)-A-ethyl]amino-2-methyliminoacetic acid (CPMA) and... 

Fig-1 SPE-LC-ESI-MS analysis (SIM mode) of two wastewater samples, spiked at different levels of concentration. Compounds (1) ciromazine, (2) oxamil, (3) metomil, (4) carbendazime, (5) thiabendazole, (6) imidacloprid, (7) acetamiprid, (8) thiacloprid... 

The procedure is very easy to reproduce and the stereoselective hydroxylation of IMI with S. maltophilia CGMCC 1.1788 may be applied to some other neonicotinoid insecticides, such as thiacloprid (Table 12.1). 

X. Bi and K. Yang, On-line monitoring imidacloprid and thiacloprid in celery juice using quartz crystal microbalance, Anal. Chem., 81, 527-532 (2009). 

Thiacloprid is a broad-spectrum systemic insecticide for use as a seed treatment and for foliar use to control aphids, leafminers, whiteflies, and other sucking and biting insects. Its oral LD50 in rats is 444-836 mg/kg. 

Most soils have a pH ranging from 4 to 9. The degradation of pesticides such as organo-phosphates and carbamates is affected by the pH of the soil. Most organophosphates are hydrolyzed under alkaline conditions, but diazinon is unstable in acid soils. Carbamates such as carbofuran are also hydrolyzed under alkaline conditions. The persistence of neonicotinoids is primarily determined by the pH. Imidacloprid and thiamethoxam are hydrolyzed under alkaline conditions, whereas thiacloprid and acetamiprid are less stable... 

Krohn, J., Behaviour of thiacloprid in the environment, Pflanzenschutz-Nachrichten Bayer, 54,281,2001. 

JMPR (2006). Report of the Joint Meeting of the FAO Panel of Experts on Pesticide Residues in Food and the Environment and WHO the Core Assessment Group, FAO Plant Production and Protection Paper, 187 (Thiacloprid), ftp //ftp.fao.0rg/docrep/fao/OlO/aO888e/aO888eOO.pdf. 

Acetamiprid, Clothianidin, Dinotefuran, Imidadoprid, Nitenpyram, Thiacloprid, Thiamethoxam... 

From the lead structure 2-nitromethylene-tetrahydro-l,3-thiazine (6, nithiazine) [7, 8], resulting neonicotinoids [9] such as the open-chain compounds, e.g., nitenpyram (8), acetamiprid (9), dothianidin (12), dinotefuran (13) (Chapter 29.2.1), the five-membered ring systems, e.g., imidacloprid (7), thiacloprid (11) (Chapter 29.2.2), and the six-membered ring systems, e.g., thiamethoxam (10), AKD 1022 (14)... 

The N-cyano-acetamidine acetamiprid (2, 1995, Nippon Soda Co., Ltd.) [16, 17, 18] contains, in analogy to 1 and the five-membered ring systems imidacloprid (11) and thiacloprid (12), the CPM moiety (see Chapter 29.2.2). It was discovered by Nippon Soda as part of its nitromethylene research program during optimization studies of special 2-N-cyanoimino compounds with an imidazoline... 

Five-membered Compounds - Imidacloprid and Thiacloprid 983 Table 29.2.2.2 Physicochemical properties of imidacloprid (1). 

Once applied on leaves, thiacloprid (9) is stable towards hydrolysis even under conditions of heavy rain und sunlight, providing sufficient plant-uptake of the substance by a continuous penetration of the active ingredient into the leaf. The half-life in water at pH 5, 7 and 9 is over 500 hours (Tables 29.2.2.6 and 29.2.2.7). 

---