in accordance with the invention , the compositions provided effective control of a wide variety of insect pests , such as cutworms , corn rootworms , wireworms , white grubs , seedcorn maggots , seedcorn beetles , flea beetles , european corn borers , corn leaf aphids and spider mites . it may be applied as granular compositions containing 1 % to 25 % by weight of phorate or terbufos and a minimum of 0 . 1 % to 2 . 5 % by weight of pyrethroid on sorptive or non - sorptive particulate granular particles such as diatomites , clays such as kaoline , attapulgite , montmorillonite , limestone , ground corn cobs , sand silica activated carbon and the like . when non - sorptive carriers are used , the surface of the particles may be wetted with the active materials and then coated with finely ground clay , talc , walnut shell flour , or other inert material . a binder or sticking agent may also be added to assure the adherence of the active material to the particles . in the case of sorptive carriers such as clays , the clay particles are treated with a polyol deactivator such as an alkylene glycol , diethylene glycol , propylene glycol , triethylene glycol , polyethylene glycol , and the like . about 1 % to 20 % by weight of the deactivator is used to avoid stability problems . the results obtained by varying the ratios of the components of the instant compositions are shown in table i . it can be seen that compositions containing 10 / 1 to 40 / 1 weight ratios of phorate or terbufos to flucythrinate are useful . for application under growing conditions normal application rates as a broadcast application for phorate and terbufos are in the 1 . 0 to 3 . 0 lb / acre range and preferred compositions of the invention would provide a minimum of from 0 . 01 to 0 . 09 lbs / acre of flucythrinate on a broadcast basis . however , it should be recognized that under varying insect pressure and climatic conditions actual rates of application may vary while maintaining 10 / 1 to 40 / 1 weight ratio of the components . table i______________________________________topical ld . sub . 50 in ng / worm ( southern armyworms , third instar ) ______________________________________treatment ld . sub . 50 ( ng / worm ) ld . sub . 50 ( ng / worm ) treatment ld . sub . 50 ( ng / worm ) ld . sub . 50 ( ng / worm ) a phorate 747 . 0 * 747 . 0 * b flucythrinate 11 . 53 * 11 . 53 * a / b 10 / 1 9 . 8 . sup .+ 95 + 9 . 5a / b 20 / 1 4 . 8 . sup .+ 95 + 4 . 7a / b 30 / 1 7 . 1 . sup .+ 202 + 6 . 7a / b 40 / 1 4 . 9 . sup .+ 189 + 4 . 7c terbufos 204 . 0 * 204 . 0 * b flucythrinate 11 . 53 * 11 . 53 * c / b 10 / 1 3 . 8 . sup .+ 37 + 3 . 7c / b 20 / 1 2 . 9 . sup .+ 55 + 2 . 8c / b 30 / 1 4 . 6 . sup .+ 129 + 4 . 3c / b 40 / 1 3 . 6 . sup .+ 136 + 3 . 4______________________________________ * average value of all tests . . sup .+ in flucythrinate equivalents flucythrinate equivalents = ( potency ratio ) ( weight of organo phosphate ) weight of flucythrinate ## str1 ## for convenience , rates of application are expressed on a broadcast basis , which represents the total amounts of material which would be present if the compositions were evenly distributed over a one acre plot . in practice , granular compositions of this type are frequently applied as &# 34 ; banded &# 34 ; treatments over the rows of planted crops and are frequently expressed in terms of ounces per 1 , 000 feet of row . thus , this type of application can result in varying expressions of concentration of materials in localized areas depending upon the spacing of the crops . expression of application rates on a broadcast basis readily enables conversion to other application practices . in order to demonstrate the present invention , the following examples are given primarily as an illustration . no specific details or enumerations contained therein should be construed as limitations on the present invention except insofas as they appear in the appended claims . all parts and percentages are by weight unless otherwise specifically designated . the general procedures for the preparation of granular pesticidal compositions of the invention . the desired quantity of granules is charged into a suitable pill coater apparatus modified by the addition of aluminum blades to facilitate the mixing and the flow of clay particles through the spray stream . the required amount of each toxicant ( and deactivator , if desired ) is placed in a stainless steel sprayer adapted so that a nozzle , screen and tip can be used . the container is pressurized to 1 . 75 kg / cm 2 . the pill coater is started and the toxicant spray stream directed down and into the flowing granules . the sprayer is shaken at intervals to insure a homogeneous spray solution . after the contents have been sprayed , the container is rinsed with a small amount of methylene chloride and spray rinsed onto the granules , and the granules dried by evaporating the methylene chloride . the desired quantity of granules is charged into a hexagonal polyethylene bowl attached to a variable speed laboratory mixer . the speed of the mixer is adjusted so that the granules cascade down the side of the bowl . the toxicant ( s ) and deactivator are placed in a 40 ml capacity devilbis bottle . a devilbis nozzle is attached to the bottle , the air pressure is adjusted to 0 . 14 to 0 . 21 kg / cm 2 and the contents sprayed onto the cascading granules . after the contents have been sprayed , the container is rinsed with a small amount of methylene chloride and spray rinsed onto the granules , and the granules dried by evaporating the methylene chloride . utilizing the above procedures and varying the amounts and ratios of flucythrinate and phorate or flucythrinate and terbufos yields the granular compositions listed in table ii below . table ii______________________________________granular compositions % toxicant by weight______________________________________composition % % number flucychrinate phorate______________________________________ 1 0 . 1 10 2 0 . 33 10 3 0 . 50 10 4 0 . 67 10 5 1 . 0 10 6 0 . 1 15 7 0 . 38 15 8 0 . 56 15 9 0 . 67 1510 0 . 75 1511 1 . 0 15______________________________________ % % flycythrinate terbufos______________________________________12 0 . 1 1013 0 . 33 1014 0 . 50 1015 0 . 67 1016 1 . 0 1017 0 . 1 1518 0 . 38 1519 0 . 56 1520 0 . 67 1521 0 . 75 1522 1 . 0 15______________________________________ the toxicity of various ratios of flucythrinate / phorate and flucythrinate / terbufos compositions to third instar southern armyworms ( spodoptera eridania ) is determined by topical application of microdrops of the mixtures in acetone solution to the dorsum of the insect . the results of these experiments which are summarized in table iii below demonstrate the improvement in insecticidal activity expressed as ld50 values , obtained with composition of the invention when compared to each of the components individually . table iii______________________________________toxicity of compositions against third instar southern armyworms topical ld . sub . 50 expressed as flucythrinate topical ld . sub . 50 , equivalentsratio component ng / worm ng / worm______________________________________ -- a . phorate 651 . 0 9 . 8 -- b . flucythrinate 18 . 510 : 1 a : b 95 + 9 . 520 : 1 a 927 . 0 4 . 8 b 12 . 5 a : b 95 + 4 . 730 : 1 a 718 . 0 7 . 1 b 11 . 3 a : b 202 + 6 . 740 : 1 a 695 . 0 4 . 9 b 9 . 4 a : b 189 + 4 . 710 : 1 c . terbufos 251 . 0 3 . 8 b 6 . 9 c : b 37 + 3 . 720 : 1 c 183 . 0 2 . 9 b 9 . 1 c : b 55 + 2 . 830 : 1 c 232 . 0 4 . 6 b 15 . 7 c : b 129 + 4 . 340 : 1 c 150 . 0 3 . 6 b 8 . 8 c : b 136 + 3 . 4______________________________________ granular treatments are appiied with planter mounted applicators and seven inch banders behind the planter shoes and in front of a press wheel . treatments are applied at planting to a plot consisting of a single row of corn ten feet long , surrounded by an aluminum lawn edging as a barrier . when the seedlings have reached the two - leaf stage , black cutworms which have been grown in a rearing room to the fourth instar , the stage at which they begin cutting plants , are released in each plot over a two week period as shown in table iv below to simulate a natural infestation of the pest in its destructive stages . three weeks after the onset of infestation the plots are evaluated and the damage attributed to the black cutworms recorded . the results of these experiments utilizing some of the compositions identified in example 1 are summarized in table v below and demonstrate the effectiveness of compositions of the invention in providing protection to seedling corn from black cutworms . table iv______________________________________artificial infestation of black cutworm larvae into plotsday of number of larvae instar ofrelease released per plot larvae______________________________________1 5 4 - 53 6 4 - 54 5 4 - 510 3 4 - 511 4 4 - 5______________________________________ table v______________________________________effectiveness of compositions of the inventionin providing protection of seedling corncompo - sition 0z lbs ac / a lbs ac / a % control comparednumber 1000 &# 39 ; ( broadcast ) ( treated zone ) untreated control______________________________________control 0 0 0 0 2 9 1 . 0 / 0 . 033 4 . 3 / 0 . 04 12 4 9 1 . 0 / 0 . 067 4 . 3 / 0 . 14 50 7 8 1 . 3 / 0 . 033 5 . 6 / 0 . 14 100 8 8 1 . 3 / 0 . 049 5 . 6 / 0 . 21 4710 8 1 . 3 / 0 . 065 5 . 6 / 0 . 28 6013 9 1 . 0 / 0 . 010 4 . 3 / 0 . 04 3815 9 1 . 0 / 0 . 003 4 . 3 / 0 . 14 4119 8 1 . 3 / 0 . 044 5 . 6 / 0 . 19 2822 9 1 . 0 / 0 . 067 4 . 3 / 0 . 29 62______________________________________ the toxicity of various ratios of fenvalerate / phorate , fenvalerate / terbufos , cypermethrin / phorate and cypermethrin / terbufos compositions to third instar southern armyworms ( spodoptera eridania ) is determined by topical application microdrops of the mixtures in active solution to the dorsum of the larval thoracic segment . after treatment of each tray of dishes a siava lime bean leaf was placed on each dish as a food source . the results of these experiments which are summarized in table vi below demonstrate the insecticidal activity , expressed as ld 50 values , obtained with composition of the invention when compared to each of the components individually . table vi______________________________________toxicity of compositions against third instar southern armyworms topical ld . sub . 50 expressed as topical ld . sub . 50 pyrethroid micrograms micrograms solution / solution / ratio component grams larval wt grams larval wt______________________________________ a . phorate 126 . 78 d . cypermethrin 1 . 7610 : 1 a : d 3 . 3720 : 1 a : d 3 . 4430 : 1 a : d 1 . 7840 : 1 a : d 2 . 46 c . terbufos 33 . 26 d . cypermethrin 3 . 9410 : 1 c : d 1 . 8020 : 1 c : d 1 . 2230 : 1 c : d 0 . 7340 : 1 c : d 0 . 78 a . phorate 120 . 66 e . fenvalerate 0 . 9910 : 1 a : e 1 . 6220 : 1 a : e 1 . 1930 : 1 a : e 1 . 1340 : 1 a : e 0 . 89 c . terbufos 68 . 84 e . fenvalerate 1 . 8510 : 1 c : e 1 . 3520 : 1 c : e 1 . 0330 : 1 c : e 1 . 8740 : 1 c : e 0 . 58______________________________________
the present invention relates to insecticidal compositions comprising a mixture of a pyrethroid and 0 , 0 - diethyl s - methyl ] phosphorodithioate or s - thio ] methyl ] 0 , 0 - diethylphosphorodithioate . the invention also relates to a method of controlling insect pests and additionally providing protection from cutworms of an agronomic crop utilizing granular compositions of the invention .