Sound Mature Kernels Research Articles

Factors influencing aflatoxin accumulation in peanut kernels and the associated mycoflora.

Accumulation of aflatoxin in Spanish peanut kernel samples from different geographical areas in Texas during 1966, as detected by the thin-layer chromatographic method, was relatively low. Analysis of samples obtained from growers using artificial drying equipment (forced air and supplemental heat), when windrow conditions were unfavorable for rapid drying, suggests that this practice reduces the possibility of aflatoxin accumulation. In general, peanuts harvested from land planted to peanuts the previous year were more highly infested with fungi and contained more aflatoxin than peanuts grown on land planted with rye, oats, melons, or potatoes the previous year. Aflatoxin incidence tended to decrease from south to north Texas. These findings verify previous research observations that moist tropical climates are conducive to fungal infestation and aflatoxin accumulation. Detection of aflatoxin in sound mature kernels (kernels screened for minimal size) indicates that the practice of screening for removal of small immature kernels and removal of obviously damaged kernels does not completely eliminate aflatoxin contamination.

Factors Influencing Aflatoxin Accumulation in Peanut Kernels and the Associated Mycoflora1

Accumulation of aflatoxin in Spanish peanut kernel samples from different geographical areas in Texas during 1966, as detected by the thin-layer chromatographic method, was relatively low. Analysis of samples obtained from growers using artificial drying equipment (forced air and supplemental heat), when windrow conditions were unfavorable for rapid drying, suggests that this practice reduces the possibility of aflatoxin accumulation. In general, peanuts harvested from land planted to peanuts the previous year were more highly infested with fungi and contained more aflatoxin than peanuts grown on land planted with rye, oats, melons, or potatoes the previous year. Aflatoxin incidence tended to decrease from south to north Texas. These findings verify previous research observations that moist tropical climates are conducive to fungal infestation and aflatoxin accumulation. Detection of aflatoxin in sound mature kernels (kernels screened for minimal size) indicates that the practice of screening for removal of small immature kernels and removal of obviously damaged kernels does not completely eliminate aflatoxin contamination.

Limiting temperature and relative humidity for growth and production of aflatoxin and free fatty acids by Aspergillus flavus in sterile peanuts.

AbstractSound mature kernels, broken mature kernels, immature kernels, and unshelled Early Runner peanuts were heat‐treated in controlled environment cabinets and inoculated with spores ofAspergillus flavus. Treatments were incubated at 97‐99% relative humidity at different temperatures ranging from 5 to 55C and also at 30C with relative humidities ranging from 55 to 99%. Samples were removed after 7 and 21 days and assayed for aflatoxin, free fatty acids, and peanut kernel moisture. The limiting relative humidity for aflatoxin production byA. flavus was 85ŷ1% relative humidity for 21 days at 30C. The limiting low temperature for visible growth and aflatoxin production by the fungus was 13ŷ1C for 21 days at 97‐99% relative humidity. Damaged kernels, however, developed some afllatoxin in 21 days at 12C. The maximum temperature for aflatoxin production was 41.5ŷ1.5C for 21 days at 97‐99% relative humidity. Fungus growth and sporulation at 43C were equal to that at 40C, but no aflatoxin was produced. Moisture content of immature kernels was higher at equilibrium with the same relative humidity than the moisture content of sound mature kernels, damaged kernels, or kernels from unshelled peanuts. There appeared to be no proportional quantitative correlation between synthesis of aflatoxin and production of free fatty acids in nonliving peanuts, but no aflatoxin was produced without a simultaneous increase in free fatty acids.

HERBICIDE MIXTURES FOR WEED CONTROL IN PEANUTS (ARACHIS HYPOGAEA L.), 1961–63*

Summary. Comparative studies of herbicides and herbicide mixtures in peanuts (groundnuts) were continued at Tifton, Georgia, U.S.A., on Tifton loamy sand during 1961–63. When applied on a dry soil surface at the ‘cracking’ stage, certain mixtures which contained dinoseb as one component with 2,4‐DES, 2,4‐DEP, or DMPA as the Other component gave control of Digitaria sanguinalis (L.) Scop. and Richardia scabra St. Hil. for the entire growing season. However, on wet soils with no subsequent rain during the first weeks or with prolonged excess moisture, mixtures were not appreciably more effective than herbicides applied singly at standard rates. Where mixtures were applied on wet soil, herbicide effectiveness was improved by timely follow‐up sprays of dinoseb at 1.5 lb/ac.Timing of application was often critical for optimum weed control. The best time was when the peanuts were cracking the ground or when the first weeds were barely visible, whichever occurred first.Mixtures permitted the use of the lowest rate of each compound on the weeds for which it was most effective.A mixture of DMPA at 6 lb/ac 4—dinoseb at 3 lb/ac applied at the ‘ground‐cracking’ stage increased the average yield of peanuts.The mixtures evaluated had no effect on shelling‐%, % sound mature kernels (SMK), mean weight per nut, or % germination. Neither did they affect taste of the peanuts or other sensory. characteristics. However, preliminary chemical analyses indicated that peanuts treated with mixtures contained more linolein and less olein than did untreated peanuts.Essais d'herbicides et de mélanges herbicides pour le désherbage dans les arachides (Arachis hypogea L.), 1961–63

Evaluation of Soil Insecticide Treatments for Control of Cyclodiene-Resistant Southern Corn Rootworms2

Experiments to control the southern corn rootworm, Diabrotica undecimpunctata howardi Barber, were carried out in southeastern Virginia during 1962.Sixty-five different formulations of 26 compounds were tested as soil-band treatments at pegging time on Virginia jumbo-type peanuts. Nine compounds: diazinon; Zinophos ( O,O -diethyl O -2-pyrazinyl phosphorothioate); GC-4072 (2-chloro-1-(2,4-dichlorophenyl)vinyl diethyl phosphate); phorate; AC-43064 (2-(diethoxyphosphinothioylimino)- 1,3-dithiolane); Bayer 25141 ( O,O -diethyl O - [p -(methyl- sulfiny1)phenyl] phosphorothioate); Bayer 39007 (o-isopropoxyphenyl methylcarbamate); UC-10854 ( m -isopropylphenyl methyl carbamate); and UC-8305 ( P -chloro-2,4,dioxa-5-methyl P -thiono-3-phosphabicyclo(4.4.0)decane), applied in granular form as soil-band treatments during mid-July effectively controlled a cyclodiene-resistant population of the southern corn rootworm. Emulsifiable concentrate treatments were ineffective. Root-worm control resulted in an increase in yield and in percent of sound mature kernels.