In highlands, the increase in altitude results in a drastic decrease in temperature (T) that delays phenological development of maize, decreasing light interception during the cycle. This could be partially overcome by increasing plant density, but information is scarce for designing specific management options. The objective of this work was to describe changes in canopy development, photosynthetic performance, biomass and yield of maize grown at contrasting plant densities (5.7 plants m−2, locally used, and 8.7 plants m−2, 50% higher). Three experiments were carried out in two high-altitude environments within the Argentinean Andean region, Hornillos (HOR, 2380 masl, 2019–20 and 2020–21) and El Rosal (ERO, 3350 masl, 2019–20), and complementary data were obtained from samplings in 8 farmer’s fields (from 2400 to 3400 masl, 2022–23). In the experiments, mean T during the first 150 days of the cycle was 33% lower at ERO, which implied 39 extra days but 25% shorter thermal time to achieve silking. The higher plant density significantly increased leaf area index and light interception at ERO, whereas at HOR, this was only evident during the second season. At the leaf level, plants grown at ERO had thicker leaves with higher chlorophyll (+36%) and nitrogen (40%) content. Photosynthetic electron transport rate at full irradiance was +20% higher at ERO but significantly varied throughout the day with lowest values in the morning, which was not observed at HOR and was not related to light intensity or stomatal conductance. At HOR, the increase in plant density did not improve light interception, nor yield in 2019–20 (with average yields of 6356 kg ha−1) but it did improve both in 2020–21 when generally lower yields were attained (4821 kg ha−1). Across farmer’s fields, increasing densities consistently reduced yield per plant (r2 = 0.57***) but improved yield per area basis, which was maximised at 10 pl m−2 as a result of a steady increase in kernel number m−2 (up to 15 pl m−2). Thus, in these high-altitude environments, increasing plant density beyond recommended (6 pl m−2) is a promising approach for improving yield, with major penalties of supra-optimum densities being related to kernel weight. Further work is needed to explore the effect of different factors limiting kernel growth, over plant density responses.

Teosinte, the wild progenitor of maize, has immense potential for providing unique traits and is more divergent compared to inbred lines and landraces. One hundred and sixty-nine teosinte-introgressed maize backcross inbred lines were developed to widen the genetic base of maize with predomestication alleles. The population was evaluated phenotypically and genotypic data of 76 SSR markers were used to map quantitative trait loci (QTLs) governing the targeted traits. Sixty-six QTLs were detected for eight plant architect-related traits that are spread over 10 different chromosomes with phenotypic variation ranging from 2.29 to 13.97%. Maximum three stable QTLs were recorded for days to anthesis (DA) followed by two for days to silking (DS), plant height (PH) and node bearing first ear (NBE). For rest of three traits namely flag leaf length (FLL), flag leaf width (FLW) and ears per plant (E/P) only one stable QTL was detected. Among the 16 common QTLs, the marker phi328178-linked QTL governed four characters (DA, DS, FLL, FLW) simultaneously, followed by umc1622-linked (ASI, FLW, E/P), umc2341-linked (DA, DS, NBE) and phi075-linked QTLs (ASI, PH, NBE) controlling three traits each. Remaining 12 QTLs controlled two characters. Molecular association between co-localized QTLs for different traits was also validated at the phenotypic level by significant correlation estimates. For eight studied traits, 53 superior lines were identified which along with parents (teosinte and maize inbred DI-103) were grouped into 12 clusters. Therefore, lines clustered independently can be combined to accumulate desirable traits for the improvement of maize.

Sweet corn (Zea mays L.) tolerance to dicamba and several other herbicides is due to cytochrome P450 (CYP)-mediated metabolism and is conferred by a single gene (Nsf1). Tolerance varies by CYP genotypic class, with hybrids homozygous for functional CYP (Nsf1Nsf1) being the most tolerant and hybrids homozygous for mutant CYP alleles (nsf1nsf1) being the least tolerant. The herbicide safener cyprosulfamide (CSA) increases tolerance to dicamba by stimulating the expression of several CYPs. However, the extent to which CSA improves the tolerance of different sweet corn CYP genotypic classes to dicamba is poorly understood. Additionally, the effect of growth stage on sweet corn sensitivity to dicamba is inadequately described. The objective of this work was to quantify the significance of application timing, formulation, and CYP genotypic class on sweet corn response to dicamba. Hybrids representing each of the three CYP genotypes (Nsf1Nsf1, Nsf1nsf1, nsf1nsf1), were treated with dicamba or dicamba + CSA at one of three growth stages: V3, V6, or V9. Across all timings, the nsf1nsf1 hybrid was the least tolerant to dicamba, displaying 16% higher crop injury levels 2 wk after treatment and 2,130 kg ha−1 lower ear mass yields compared with the Nsf1Nsf1 hybrid. The V9 growth stage was the most susceptible time for dicamba injury regardless of genotypic class, with 1.89 and 1,750 kg ha−1 lower ear mass yields compared with the V3 and V6 application timings, respectively. The addition of CSA to dicamba V9 applications reduced the injury from dicamba for all three genotypic classes; however, it did not eliminate the injury. The use of Nsf1Nsf1 or Nsf1nsf1 sweet corn hybrids along with herbicide safeners will reduce the frequency and severity of injury from dicamba and other CYP-metabolized herbicides.

In this study, maize landraces, previously collected from different regions of Turkey through a national maize breeding project, were screened for kernel oil content and oil quality. After a seed reproduction in 2017, the screening trial was conducted in 2018, using an Augmented Experimental Design with 192 local maize populations along with seven check hybrids. Data were collected on oil, oleic acid, linoleic acid, monounsaturated (MUFA), polyunsaturated and saturated fatty acids, total carotenoid and total tocopherol contents. The results showed that there was a considerable amount of genetic variation among the Turkish maize landraces for almost all the traits investigated in this study. Some of the evaluated landraces are available that could be considered as high oil variety or special genotypes in terms of certain oil quality traits. Landraces had significantly higher values than checks for oil content, oleic acid, MUFA and tocopherol contents. Genetic analyses suggest that the kernel quality traits could be successfully manipulated using the investigated plant material. Heritability values were found high for all the traits of interest, except for saturated fatty acid and total carotenoid content. The promising landraces detected in this study could be exploited in future breeding programmes upon further evaluations at the population level.

The supplementation of nitrogen can be increased by the use of nitrogen-fixing, diazotrophic bacteria such as Azospirillum brasilense. These bacteria can act to promote plant growth in various plant species, including corn (Zea mays L.). However, there is a need to understand the behavior of these bacteria in different agricultural systems. The objective of this study was to evaluate the effect on the growth and yield of corn inoculated with A. brasilense, and to identify the type of farming system which benefited most from the use of A. brasilense-based inoculants. The experiment conducted over two corn crop seasons was arranged in a 6 × 2 factorial scheme, consisting of six farming systems and the presence or absence of inoculation with the bacteria A. brasilense. The farming systems were derived from a long-term experiment with different fertilization systems that has been conducted since 1984. Among these systems, there were three conventional systems (CNT1: conventional no-till without fertilizer; CNT2: conventional no-till with 150 kg ha−1 of mineral fertilizer + 50 kg ha−1 of urea; CNT3: conventional no-till with 300 kg ha−1 of mineral fertilizer + 100 kg ha−1 of urea), and three organic systems (ONT1: organic no-till with 40 m3 ha−1 of organic compost; ONT2: organic no-till with 20 m3 ha−1 of organic compost; ONT3: organic no-till with 40 m3 ha−1 of organic compost and intercropped with Canavalia ensiformis). Although the Azospirillum population in the soil before planting was the same for all six systems, the count in the rhizospheric soil was higher in the organic systems, and there was no increase in that count due to inoculation. In this study, the only difference observed was within the CNT1 system, between the inoculated (CNT1-I) and uninoculated (CNT1-NI) treatments. In this system, inoculation resulted in an increase in plant height, in addition to higher concentrations of foliar N and P, and a higher plant survival rate, which culminated in higher yield. Corn inoculated with A. brasilense in the CNT1-I treatment showed a significant increase in yield—2839 kg ha−1 higher than that recorded for CNT1-NI. This study shows that, in the conventional low input treatment CNT1-I, inoculation with A. brasilense resulted in an increase in corn growth and yield.

Glyphosate resistance has evolved worldwide. Glyphosate is also the most used herbicide in Spain, and current changes in herbicide usage patterns can increase the risk of glyphosate resistance development. The objective of this study was to assess the glyphosate sensitivity of different selected weed species important in Spanish maize (Zea mays L.) fields. To this end, dose–response experiments were conducted under controlled conditions in a growth chamber to examine variation in glyphosate sensitivity among populations of five grass weed species and eight broadleaf weed species that are commonly found in the maize fields in Castilla y León, the biggest maize-growing region in Spain. The glyphosate doses that caused growth reduction by 50% (GR50) were calculated for each weed population. No populations were resistant to glyphosate. In addition, baseline values of glyphosate sensitivity were determined for each weed species. The GR50 baseline values ranged from 10.25 to 53.23 g ai ha−1 for the dicotyledonous weed species and from 16.05 to 66.34 g ai ha−1 for the monocotyledonous weed species. The ratio between the GR50 values of the least and most sensitive populations was used to determine the SI50 (sensitivity index at 50% growth reduction) for each weed species. The SI50 values showed a 1.4- to 3.3-fold difference in sensitivity for dicotyledonous weed species and 1.4- to 2.4-fold difference for monocotyledonous weed species. The sensitivity index was also calculated as the ratio between the GR50 values of the least sensitive population and the baseline GR50 value estimated for a range of susceptible populations (SI50b). SI50b values showed a 1.2- to 1.6-fold difference in sensitivity for dicotyledonous weed species and 1.1- to 1.2-fold difference for monocotyledonous weed species. The sensitivity data generated in this study provide a reference for determining time-dependent changes in glyphosate sensitivity in the commonly found weeds in the maize fields of Castilla y Léon.

The mirid bug Apolygus lucorum (Meyer-Dür) (Hemiptera: Miridae) is a major pest on cotton, fruit trees and other crops in China. A. lucorum adults often switch host plants in the agro-ecosystem, and such host-plant switching may promote more rapid population growth of A. lucorum. Here, we examined the population fitness of A. lucorum on different combinations of two plant foods [fresh maize kernels (Zea mays) and green bean pods (Phaseolus vulgaris)] in the laboratory when reared either individually or in groups. Our results suggested that, compared with A. lucorum nymphs reared on green bean alone, the survival rate, developmental rate, and adult weight significantly increased when they were fed fresh maize kernels for both rearing methods. Both two-plant combinations of foods (i.e., maize as nymphal food then green bean as adult food, and green bean as nymphal food then maize as adult food) generally prolonged adult longevity, improved female fecundity, and higher egg hatching rate compared with maize or green bean as food for both nymphs and adults. The combination of nymphs with maize and adults with green bean showed the highest population growth rate for both individual and group rearing of mirid bugs. Host food switching greatly promoted the population growth of A. lucorum, and suggests a new diet for laboratory rearing of A. lucorum.

The objectives of this study were to analyse the maize diversity in the southeast of Coahuila State in Mexico and to identify a representative subset that encompasses the majority of the diversity in the region of study. Seventy-seven native maize populations were first explored and given a race classification followed by a morphological description based on selected quantitative ear traits using 10 representative ears from the collected samples. The differences between maize populations from the adaptation area and the relationships between and within groups in the region of study indicate the usefulness of the ear traits to describe maize diversity. Two main groups were identified that summarized the maize diversity. The first group, the conical ear complex, includes populations adapted to highland altitudes (Conico Norteño Race). The second group, the cylindrical ear complex, represents populations adapted to lowland and intermediate altitudes (Raton and Tuxpeño Norteño). Using the phenogram, a subset of 18 out of the 77 maize populations (23.4%) was defined that accounts for the variation between and within the different race complexes. This subset also includes at least one representative population from each of the less represented types. The final subset, representing a sample of maize diversity, can be used to establish strategies for conservation and use, such as participatory conservation and management, or it can be used to develop breeding techniques for improving the land race populations within the region of study.

Cover crops can offer erosion protection as well as soil and environmental quality benefits. Cereal rye (Secale cereale L.) is the most commonly used winter cover crop in corn–soybean rotations in the upper Midwest of the USA because of its superior winter hardiness and growth at cool temperatures. Cereal rye cover crops, however, can occasionally have negative impacts on the yield of a following corn crop, which discourages broader adoption and introduces substantial risk for corn farmers employing cover crops. We hypothesized that because cereal rye shares some pathogens with corn, it may be causing increased disease in corn seedlings planted soon after cereal rye termination. To test this, we performed a series of experiments in a controlled environment chamber to assess the response of corn seedlings with and without a commercial fungicide seed treatment to the presence of cereal rye or other species of cover crops that were terminated with herbicide prior to corn planting. Our results indicate that under cool and wet conditions, cereal rye reduces corn seedling growth performance and increases incidence of corn seedling root disease. Fungicide seed treatment had limited efficacy in preventing these effects, perhaps because environmental conditions were set to be very conducive for disease development. However, hairy vetch (Vicia villosa Roth) and winter canola (Brassica napus L.) cover crops had fewer negative impacts on corn seedlings compared with cereal rye. Thus, to expand the practice of cover cropping before corn, it should become a research priority to develop alternative management practices to reduce the risk of corn seedling root infection following cereal rye cover crops. Over the longer term, testing, selection and breeding efforts should identify potential cover crop species or genotypes that are able to match the winter hardiness, growth at cool temperatures and the conservation and environmental quality benefits of cereal rye, while avoiding the potential for negative impacts on corn seedlings when environmental conditions are suitable for disease development.

A linear programming model was used to determine which crop rotations and weed management systems result in the highest net farm income for each of three farm sizes (120, 240, and 480 hectares) under alternative tillage systems. Test plot data for the years 1981 through 1988 from the Purdue University Agronomy Farm, which has highly productive, well-drained soils, were analyzed. Net incomes for no-till tillage systems on all farms in the model were consistently and significantly lower than incomes for moldboard and chisel plow tillage systems due to slightly lower yields and substantially higher herbicide costs. Generally, net farm incomes were slightly higher with a moldboard plow versus chisel plow tillage system. Also, as farm size increased, per hectare net incomes increased. About 80% of the time under moldboard or chisel plow tillage systems, the model chose as optimal the lowest of three herbicide application rates. A corn/soybean rotation was chosen as optimal on 56% of the farm area analyzed, versus 25% for continuous corn and 13% for a corn/soybean/wheat rotation.

Greenhouse and laboratory experiments showed that the biological activity of EPTC (S-ethyl dipropylthiocarbamate) + R-25788 (N,N-diallyl-2,2-dichloroacetamide) was lost more rapidly in soils if they had been previously treated with this herbicide. Treatments which reduced or eliminated the microbial activity in the soil restored the herbicide activity in ‘problem’ soils. A combination of 2 kg/ha of the insecticide fensulfothion (diethyl-4-methylsulphinyl phenyl phosphorothionate) with EPTC + R-25788 also restored the biological activity of the herbicide. Field trials confirmed the decreased biological activity with repeated use of EPTC + R-25788; other herbicides recommended for grass weed control in corn (Zea mays L.) performed satisfactorily in these ‘problem’ soils. The performance of EPTC + R-25788 was improved by a rotation away from it for one season (using another herbicide) but the level of activity was still below that obtained in a soil treated with EPTC + R-25788 for the first time. A new formulation of EPTC + R-25788 containing a herbicide extender R-33865 (O,O-diethyl-O-phenyl phosphorothioate) was not affected by the enhanced microbiological breakdown and provided effective season-long weed control in the ‘problem’ soils.

A large crabgrass population (PW2) that demonstrated resistance to fluazifop-P and sethoxydim was identified in Wisconsin during 1992. Dose-response experiments were conducted in the greenhouse to determine the level of resistance of a PW2 large crabgrass accession to aryloxyphenoxypropionate (APP), cyclohexanedione (CHD), and other herbicide chemistries relative to a large crabgrass accession (A310) which was susceptible to APP and CHD herbicides. Based on shoot dry biomass reduction, the PW2 accession was 337- and 59-fold resistant to sethoxydim and fluazifop-P, respectively, relative to the A310 accession. Resistance of the PW2 accession to fenoxaprop, haloxyfop, quizalofop, and diclofop ranged from 18- to 29-fold. The PW2 accession was only 7-fold resistant to clethodim. Both large crabgrass accessions were susceptible to imazethapyr and linuron. These results suggest that APP and CHD herbicides will be ineffective for the management of the PW2 accession. An integrated approach including cultural, mechanical, and alternative chemical methods, should be implemented for the management of the PW2 accession and to prevent additional resistance problems.

In field and greenhouse studies, alachlor [2-chloro-2′,6′-diethyl-N-(methoxymethyl)acetanilide] was found to antagonize buthidazole {3-[5-(1,1-dimethylethyl)-1,3,4-thiadiazol-2-yl]-4-hydroxy-1-methyl-2-imidazolidinone} injury to corn (Zea mays L.) when both herbicides were preplant incorporated. Similar results were found with five of seven other acetanilide herbicides tested. The antagonism between buthidazole and alachlor also occurred with common cocklebur (Xanthium pensylvanicum Wallr.) and ivyleaf morningglory [Ipomoea hederacea (L.) Jacq.] but not with five other weed species. Preplant-incorporated applications of alachlor had little to no effect on the response of corn to postemergence applications of buthidazole, but alachlor increased the susceptibility of ivyleaf morningglory to postemergence applications of buthidazole. No antagonism was observed when alachlor was included in postemergence applications of buthidazole to corn or ivyleaf morningglory.

Effects of fluazifop-butyl {(±)-butyl 2-[4-[(5-(trifluoromethyl)-2-pyridinyl)oxy] phenoxy] propanoate} on cellular uptake and incorporation of 14C-leucine, 14C-uridine, and 14C-thymidine into protein, RNA, and DNA, respectively, were evaluated in corn (Zea mays L.) coleoptiles and soybean [Glycine max (L.) Merr.] hypocotyls. Uptake of 14C-leucine in corn coleoptiles was inhibited by fluazifop-butyl at 10-4 to 10-7 M, which was related to reductions in incorporation of 14C-leucine into protein at 10-4 to 10-6 M. The effect of fluazifop-butyl on 14C-leucine uptake and incorporation was reduced by 2 × 10-6 M 2,4-D [(2,4-dichlorophenoxy)acetic acid], indicating antagonism between these herbicides. RNA and DNA synthesis were inhibited at 10-5 and 10-4 M. Protein synthesis in soybean hypocotyls was stimulated by 10-7 and 10-6 M fluazifop-butyl 33 and 27%, respectively, and inhibited by 10-4 M 50%. RNA and DNA synthesis were also inhibited by 10-4 M in soybean.

Benzyl isothiocyanate (BITC) was formulated in dry granules with tung oil and calcareous loess to facilitate safe handling of the water-sensitive lachrymator. Crop and weed seeds were exposed to granular BITC at 40 mg ai/kg (w/w) substrate on moist sand for 2 days. When the pretreated seeds were washed with water and placed on BITC-free sand in a germination chamber for 15 days, germination in comparison to untreated seeds was 0 to 8% for pitted morningglory (Ipomoea lacunosa L. # IPOLA), sicklepod (Cassia obtusifolia L. # CASOB), milo [Sorghum bicolor (L.) Moench. ‘Funks G-522DR’], and red rice (Oryza sativa L. # ORYSA) seeds; 15 or 16% for velvetleaf (Abutilon theophrasti Medic. # ABUTH) and johnsongrass [Sorghum halepense (L.) Pers. # SORHA]; and 39% for barnyardgrass [Echinochloa crus-galli (L.) Beauv. # ECHCG]. Subjecting milo seeds to moist sand medium that contained BITC granules at 10, 20, and 40 mg ai/kg substrate reduced germination of milo by 78, 97, and 100%, respectively. However, BITC granules applied to the growth medium 2 to 4 days prior to sowing seeds had little effect on germination and growth of milo or sicklepod. Thus, BITC-treated soil soon became safe for newly sown seeds, but seeds present in soil when the toxin granules were applied failed to recover from exposure to BITC and deteriorated within 15 days.

A standard weed management system (system I) had a higher return above variable costs than did an intensive weed management system (system II) for two eastern Colorado cropping rotations. For continuous corn (Zea mays L.), the return above variable costs averaged $18.85/ha more under system I than under system II. For a barley (Hordeum vulgare L.)-corn-sugarbeet (Beta vulgaris L.) rotation, the return above variable costs averaged $20.48/ha more under System I than under System II. Based on alternative input (herbicide) and product prices, higher herbicide costs favored the standard weed management system, whereas higher crop prices favored the weed management system with the higher yields adjusted for quality. The probability that returns above variable costs differed between the two weed management systems depended upon the level of product prices and herbicide costs.

Field experiments were conducted to determine effects of adding 2.8 kg/ha (NH4)2SO4 and/or substituting BCH 81508 S for crop oil with sethoxydim applied to large crabgrass, corn, johnsongrass, and common bermudagrass. Adding (NH4)2SO4 did not affect control of johnsongrass or common bermudagrass but did increase control of large crabgrass and corn by 6 and 15%, respectively. Cora control was enhanced more by (NH4)2SO4 at lower sethoxydim rates. Substituting BCH 81508 S for crop oil increased seedling johnsongrass, large crabgrass, common bermudagrass, rhizome johnsongrass, and corn control by 7, 9, 9, 10, and 15%, respectively. A sethoxydim rate by spray adjuvant interaction was observed with seedling johnsongrass, common bermudagrass, and corn where response to BCH 81508 S decreased as sethoxydim rates increased. The effects of substituting BCH 81508 S for crop oil and adding (NH4)2SO4 were independent.

Wild carrot is becoming a serious weed problem in Michigan continuous no-tillage crop production. Greenhouse and field research was conducted to identify effective management strategies for wild carrot control in no-tillage cropping systems. In the greenhouse, PRE applications of acetochlor plus dichlormid (5.8:1 w:w), cyanazine, linuron plus chlorimuron (18:1), and metribuzin plus chlorimuron (10:1) and POST applications of bentazon, CGA-152005, clopyralid, cyanazine, and MON 12000 provided the greatest control of wild carrot seedlings. In the field, PRE and POST treatments containing chlorimuron consistently controlled overwintered wild carrot greater than 71% at 30 d after the POST application in no-tillage soybean. Atrazine, MON 12000, nicosulfuron, and primisulfuron applied POST consistently controlled overwintered wild carrot greater than 78% at 30 DAT in no-tillage corn. Glyphosate at 0.84 or 1.68 kg ae/ha applied in October to established wild carrot provided greater than 74% control the following spring. Early preplant (EPP) applications of glyphosate at 0.84 kg/ha in no-tillage soybean gave 95 and 24% control of overwintered wild carrot in St. Clair and Lenawee Counties, MI, respectively, at 70 DAT. PRE applications of glyphosate at 0.84 kg/ha controlled overwintered wild carrot less than 69% at 58 DAT in no-tillage corn and soybean. Fall applications of 2,4-D ester at 1.12 kg ae/ha provided 18 and 88% control of wild carrot the following spring in Clinton and Lenawee Counties, respectively. EPP applications of 2,4-D ester at 1.12 kg/ha provided 7 and 72% control of overwintered wild carrot in St. Clair and Lenawee Counties, respectively.

Laboratory experiments were conducted to determine the selectivity and inhibitory activity of BAS 517 using whole seedlings or root tips of corn and soybean. Effects of BAS 517 on the morphology of corn root tips were examined as well. Etiolated corn seedlings showed high sensitivity to BAS 517; soybean seedlings were not affected. Growth inhibition of corn varied with concentrations of BAS 517 and incubation time. Radicles of corn were more sensitive than mesocotyls and coleoptiles. Root meristems were the first to show symptoms (reddening tissue followed by cessation of root growth). Results using root tips were similar to those using whole seedlings. However, root tips appeared to be more sensitive than whole seedlings. Concentrations of 0.1 and 10 μM of BAS 517 caused severe vacuolization of cells in the 0.2-cm root tip of corn. A pattern of decreasing injury from epidermal cells toward the centers of roots was observed.

Quackgrass biotypes collected from 15 locations exhibited differential response to primisulfuron at 20 g ha−1 in field experiments at Hudson, NY during 1990 and 1991. Quackgrass control ranged from 23 to 100% 77 days after application (DAA) in 1990 and from 38 to 100% 88 DAA in 1991. The biotype from Montpelier, OH was the most tolerant both years. Differential response of quackgrass biotypes from five locations was confirmed in greenhouse experiments. The primisulfuron rate required to reduce shoot regrowth by 50% in the greenhouse was estimated at 15, 15, 17, 17, and 37 g ha−1 for biotypes from Amherst, MA; Mahnomen MN; Fargo, ND; State College, PA; and Montpelier, OH, respectively. Quackgrass shoot regrowth was reduced more when primisulfuron was applied with the linear alcohol ethoxylate additive 1412-70 compared with Scoil, Sylgard 309, Agridex, or X-77.