Mixed Bottom Research Articles

Insecticidal Control of Fall Armyworm, Corn Earworm, and Corn Silkfly on Sweetcorn, 1997

Abstract Six raised beds, 32 inches wide and 240 ft long on 6 ft centers, were prepared in a semiclosed subirrigated field: They were fumigated with 67/33% methyl bro-mide/chloropicrin at 220 lbs/acre, fertilized with a bottom mix of 700 lb/acre 5-16-8 and 250 lb/acre at 19-0-19 lb/acre top mix laid in 2 bands 4 inches in from the edge on each side of the bed and covered with black polyethylene mulch. An additional 40 lb of N/acre of 6-2-6 was injected on 16 May. Beds were divided into two, 3-row sets separated by a 15-ft roadway. The center row of each 3-row set was planted on 10 Mar to provide pest inoculum. The remaining 4 rows were each divided into 5 single row plots in a RCB design with 4 replications and planted 23 Apr by hand at 10 inch spacing. Five weekly applications were initiated 20 May using a high clearance sprayer equipped with 2 overhead nozzles fitted with ceramic Albuz “yellow” hollow cone noz-zles per row with delivery pressure of 200 psi at a rate of 22 gpa. A pre-treatment sample of 100 plants per block and 60 ears per inoculum row on 16 May showed that 24% plants were damaged (primarily by FAW) and 85% ears had CEW and 33% FAW. Foliar damage was evaluated weekly for 3 weeks on 20 randomly selected plants per plot after the initiation of the treatments. Damage was assessed as a percentage of the total loss from the top three leaves in the whorl. The number and size (in 3 categories) of larvae in each whorl was noted. Ears were harvested on 20 and 26 Jun from the same 20 plants in the center of each plot. Ears were evaluated for marketability noting total weight of ears in each category. Nonmarketable ears were further examined and any larvae present identified to species.

Control of Lepidopteran Pests on Cabbage with Emamectin Benzoate and Bacillus Thuringiensis, 1997

Abstract Two sets of 3 beds, 240 ft long on 6-ft centers and separated by a 15-ft drive, were prepared by fumigating with methyl bromide/chloropicrin 67/33% at a rate of 220 lbs/acre, fertilizing with a bottom mix of 800 lbs/acre 5-16-8 and a top mix of 210 lbs/acre of 19-0-19, and covering with a black polyethylene mulch. The center row in each set of 3 was planted 20 Nov 1996 with collard seedlings var ‘Georgia’ seeded 15 Oct 96 to provide inoculum of the target pests. Greenhouse-grown seedlings planted in flats on 10 Dec 1996 were transplanted in single rows on 29 Jan 1997 at 18-inch spacing and watered by a semiclosed irrigation system. An additional 46 lbs/acre of N and K was injected into the beds 30 days after transplanting and plants were sprayed with Bravo 720 at 1.5 pt/acre after transplanting for disease control. Each row of cabbage was considered one of 4 replicates and divided into 5 plots 34 ft long 5; to which treatments were randomly assigned in a RCB design. Sixty plants per row were checked for the presence of target pests on 13 Mar and treatments initiated after an average of 0.48 DBM larva per plant was observed. All treatments were sprayed weekly beginning 17 Mar for 5 weeks at a rate of 32 gpa , using a high-clearance sprayer at 200 psi of pressure and 3 yellow hollow cone AlbuzTM ceramic nozzles per row. Weekly evaluations 3 to 5 days after application on 12 randomly selected plants per plot consisted of counts of live DBM, CSW, CL larvae and a damage rating on 5 upper wrapper leaves and 3 J outer leaves of the head. Damage was rated as 0 = none, 1 = minor feeding (0-1 %) on wrapper leaves, 2 = 2-5% wrapper leaf surface, no head damage, 3 = 6-10% wrapper leaf area consumed with minor feeding on head, 4=11-30% wrapper leaf area consumed with moderate feeding on head, 5 = >30% wrapper leaf area eaten, considerable feeding and numerous feeding scares on head. At harvest the 15 largest heads per treatment were selected and graded for marketability based on amount of insect damage. The “Fancy” category had no insect damage to the head when harvested, whereas “standard” heads were damaged but could be salvaged for market by peeling the damaged outer leaves. The weight of the remaining “Standard” heads was added to the weight of the “Fancy” heads to obtain an estimate of marketable weight. A category of culls consisted of heads that were not salvageable due to extensive ; insect damage.

Elusive Ocean Mixing Nabbed

SAN FRANCISCO —Oceanographers have had a hard time identifying where and how the oceans' deep, salty bottom waters mix with the overlying warmer layers. But a deep-diving instrument package has discovered a clue, researchers reported last month at the American Geophysical Union meeting here: a zone of intense mixing over a region of rugged ocean bottom off Brazil, 5600 meters down. By churning the overlying waters, regions of rough bottom may account for much of the oceans' missing mixing.

Control of Tomato Pinworm (Tpw) with Abamectin in Staked Tomato, 1996

Abstract Tomato seedings “Agriset” from a commercial plant house were transplanted on 7 Mar 96, 18 in. between plants, into raised beds 32 in. wide on 6-ft centers covered with black polyethylene film mulch. A dry bottom mix of 50 lbs N, 160 lbs P and 80 lbs K per acre had been placed at the bottom of the beds and an additional 3.25 lbs per acre N and K were fertigated 3 times a week by drip irrigation. The plants were sprayed weekly with an alternating combination of Maneb 80 WP at 1.5 lb/acre plus Kocide 101 at 2 lb/acre and Bravo 720 at 2 pt/acre for disease control. Dipel was added to the disease control sprays when needed at a rate of 1 lb product/acre. Two wing-type traps from AgriSense containing TPW pheromones were set out on 23 Apr. 15 feet to the east and west of the trial area to monitor moth activity. Mean number of moths captured rose from 1.4 per night on 26 Apr to a peak of 33.6 on 10 May, later declining to 8.0 on 20 May. Plots, 30 ft long and 2 rows, wide were assigned one of 3 treatments in a CRB design with 4 replications. All treatments were sprayed weekly from 1 May to 15 May for three applications at 69 gpa using a high clearance sprayer with 2 booms of 3 Yellow Albuz hollow cone nozzles each for a total of 6 per row and operating pressure of 200 psi. Plants (10 per row or 20 total) were evaluated before treatment on 30 Apr and again on 6 and 13 May by counting live and dead miners. Damage for the entire plant was assessed on a rating scale of 1-6: “1” = no apparent damage; “2” = 0-1% of leaflets damaged; “3” = 2-5% damaged; “4” = 6-10% damaged; “5” = 11-30% damaged; and “6” = >30% damaged. Fruit was harvested 21 May from 20 plants per plot and the marketable fruit graded on a commercial table with weights and numbers recorded. Unmarketable fruit was separated into categories of TPW damage, other insect damage and damage due to disease.

Control of Diamondback Moth (Dbm) with Emamectin and Bacillus Thuringiensis Endotoxins, 1996

Abstract Six beds 32 inches wide and 240 ft long were fumigated with methyl bromide/chloropicrin 67/33 at a rate of .220 lbs/acre, fertilized with a bottom mix of 800 lbs/acre 5-16-8 and a top mix of 500 lbs/acre of 19-0-19, and covered with black polyethylene film. The center bed of each of 2 sets of 3 beds on 6-ft centers separated by a 15 ft drive middle was planted on 5 Dec 1995 with collard seedlings var ‘Georgia’ to provide target pest inoculum. Cabbage seedlings were transplanted 29 Jan into single rows on the remaining 4 beds at 18 inch spacing. Beds were subsurface irrigated with a semi-closed system and plants sprayed with Bravo 720 at 1.5 pt/acre for disease control. Each bed of cabbage was considered a block and divided into 7 plots 34 ft long in a RCB design with 4 replications and 7 treatments. A precount on 1 April of 20 plants per replication yielded an average 1 DBM larva and 0.8 DMB pupa per plant. Treatments were applied on 2, 11, and 17 Apr at a rate of 65 gpa using a high clearance sprayer equipped with 5 yellow hollow cone Albuz ceramic nozzles per row and operating at 200 psi of pressure. A nonionic surfactant, ASPA 80, was tank mixed at the rate of 16 oz/100 gal of spray which was made up with water at pH 7.2. Proclaim was not applied on 11 Apr at the request of the company representative. Ten randomly selected plants per plot were evaluated weekly 4 to 7 DAT. Five wrapper leaves and 3 inner (head) leaves per plant were inspected for larvae classified in 3 size categories. A damage rating was determined for each plant where 1 = no apparent damage, 2 = 0-1 % surface area damage to wrappers, 3 = 2-5% damage to wrappers but none to head, 4 = 6-10% damage to wrappers, 0-5% damage to head, 5 = 11-30% damage to wrappers, 5-15 damage to head 6 = >30% damage to wrappers, 15% damage to head. Evaluations were recorded on Pesticide Research Manager version 4.06. The 15 largest heads in each plot were selected and graded for marketability on 25 Apr based on 2 levels of stringency: “Fancy” with no insect damage on the wrapper leaves or head, and “Standard” with less than 10% insect damage on wrapper leaves and less than 5% on the head, limited to the 2 outer leaves.

Control of Silverleaf Whitefly (Swf) on Tomato Using Sanmite Applied with Hydraulic and Airboom Sprayers, 1996

Abstract Tomato seedlings “Agriset” from a commercial plant house were transplanted on 7 Mar 96, 18 in between plants, into raised beds 32 in wide and 250 ft long on 6-ft centers. They were covered with black polyethylene film mulch. A dry bottom mix of 50 lbs N, 160 lbs P and 80 lbs K per acre was placed at the bottom of the beds and an additional 3.25 lbs per acre N and K was fertigated 3 times a week by drip irrigation. The plants were sprayed weekly with an alternating combination of Maneb 80 WP at 1.5 lb/acre plus Kocide 101 at 2 lb/acre and Bravo 720 at 2 pt/acre for disease control. Dipel was added to the disease control sprays when needed at a rate of 1 lb product/acre. Each of the 4 beds was used as a replication divided into 5 plots separated by 2-ft buffers, with each 48-ft plot randomly assigned to 5 treatments. Applications were initiated 16 May when whitefly population was established and continued weekly for 3 weeks. Spray was delivered using two different types of spray equipment: a high clearance sprayer utilizing an hydraulic pump operating at 200 psi, delivering spray through 6 Yellow Albuz hollow cone nozzles, 3 per drop boom at a volume of 69 gpa at 2.5 mph, and a Berthoud airboom sprayer delivering spray material at 50 psi through 6 Brown Albuz nozzles, atomized by an airblast 172 mph and dispensing at a volume of 35 gpa. Spray coverage was evaluated on 8 May by using water sensitive papers and spectophotmetric analysis of FD&C#1 blue dye deposited on paper targets. Plants were evaluated weekly for the presence of whitefly adults, eggs, nymphs, pupa and parasitized pupae on a trifoliate from the 6th node of 8 randomly selected plants per plot. Counts were made using stereoscopic microscope by placing a 1 cm sq template twice on each side of the midvein of each leaflet (4 cm2/leaflet = 12 cm2/trifoliate = 96 cm2 per plot). Adult whitefiies were evaluated by striking plants 5 times with a 9.5" X 13" pie pan painted black and covered with a 9:1 oil/detergent mixture (N = 6/plots). Fruit was not harvested for evaluation because a heavy infestation of pin worm and high incidence of disease on many of the plots would have rendered the data of little value.

Control of Two Lepidopterous Cabbage Pests with Recombinant and Kurstaki Bacillus Thuringiensis, Spring 1995

Abstract Greenhouse-grown seedlings planted in Speedling trays 30 Dec were transplanted at 18-inch spacing into 4, 32-inch single-row beds 240 ft long, mulched with black polyethylene on 31 Jan at the Southwest Florida Research and Education Center near Immokalee, Fla. Beds were prepared by fumigating with methyl bromide/chloropicrin 67/33 at a rate of 220 lbs/acre, fertilized with a bottom mix of 800 lbs/acre 5-16-8 and a top mix of 500 lbs/acre 19-0-19, and subsurface irrigated. Plants were sprayed weekly from 6 Feb to harvest with Bravo 720 at 1.5 pt/acre for disease control. Each row of cabbage was a replicated block, the two pairs of which were separated by a 15 ft drive middle, with each pair being separated by 12 ft with a row of collards in between planted 15 Nov to provide pest inoculum. Blocks were divided into 6 plots 40 feet long containing 30 plants. Six treatments were replicated four times in a RCB design. The presence of DBM and CSC larvae was confirmed on 20 Mar and treatments were initiated 21 Mar. All treatments were sprayed weekly for a total of 4 applications at 43 GPA using 5 yellow hollow cone Albuz nozzles per row from a high clearance sprayer at 200 psi of pressure, except the last application which was made with a CO2 backpack sprayer at 50 psi at the same rate. Water was at pH 7.2 and a nonionic surfactant, ASPA 80 was added to the spray at the rate of 16 oz/100 gal of spray. Weekly evaluations were made five to seven days post spray on 10 randomly selected plants per plot. Eight leaves were evaluated per plant, the 5 outer head leaves and 3 inner wrapper leaves. Total number and size of DBM and CSC live larvae for each plant were recorded and percent leaf damage was rated on a 1 to 6 scale where 1 = no damage, 2 = 1%, 3 = 2% to 5%, 4 = 6% to 10%, 5 = 11% to 30% and 6 = > 30% damage. The 20 largest heads per treatment were selected for harvest and graded for marketability based on amount of insect damage to the head and inner 2 wrapper leaves. Heads were considered unmarketable if there was insect damage in excess of 5% on the head or 10% on the wrapper leaves.

Control of Southern Armyworm in Staked Tomato with an Ecdysone Agonist, Fall 1993

Abstract Beds of 32 inch width on six foot centers were prepared in sandy soil at Immokalee Florida, fumigated with 33/66 choropicrin/methyl bromide applied at 220 lbs/acre, fertilized with a bottom mix of 800 lbs/acre of 5-16-8 and a top mix of 500 lbs of 19-0-30, and covered with whiteface polyethylene mulch. Greenhouse grown tomato seedlings were transplanted 18 inches apart into single rows on 1 Oct and watered by seepage irrigation. Plants were sprayed weekly with a fungicide, Maneb 80 W, at a rate of 1 lb/acre and standard cultural practices of pruning and staking was followed. Three rows 240 feet long were divided into 12, 3-row plots 20 ft long. Blocks (4) ran lengthwise, with 3 treatments randomly assigned to each giving an RCB design 3 treatments and 4 replications. Two treatments consisted of RH-5992 2F applied at rates of 0.06 and 0.12 lb AI/100 gal with an unsprayed check as the third treatment. Weekly sprays commenced 5 Nov 1993 when the presence of army worms was noted and continued until 17 Dec 1993 for a total of seven applications. An adjuvant, APSA 80® (Amway Corp.) was added to each spray tank at the rate of 0.06%. Sprays were applied with a tractor-drawn hydraulic boon sprayer employing a diaphragm pump operating at 200 psi. The boom carried two drop lines per row with Albuz ATR® red nozzles increased front three to four after the second spray with a commensurate increase in spray volume from 91 gal/acre to 105 gal/acre. Eight plants were selected weekh at random from the center of each row from 4 Nov to 20 Dec 1993 for visual evaluation of defoliation and to count larvae, predominantly SAW although some BAW were encountered. All fruit of marketable size was harvested on 3 Jan 1994. Marketable fruit was separated into extra large, large, medium, and small USDA categories with a mechanical grader and insect-damaged culls counted separately. Value per acre was estimated based on a $12/10/9; 7, respectively per 25 lb box market.

Control of Silverleaf Whitefly and Tomato Pinworm on Staked Tomato with Chemical and Biological Insecticides, Spring 1994

Abstract Beds (32 inch width) were prepared in sandy soil on six foot centers, fumigated with a 67/33% mixture of methyl bromide and chloropicrin applied at 220 lbs/acre, fertilized with a bottom mix of 800 lbs/acre of 5-16-8 and a top mix of 500 lbs of 19-0-30 and mulched with whiteface polyethylene film. Greenhouse grown tomato seedlings were transplanted 18 inches apart on 1 Mar 1994 into single rows and watered by subsurface seepage irrigation. Plants were sprayed weekly with 3.0 lb/acre Kocide DF plus 1.0 lb/acre Maneb 80W rotated with Bravo 720 applied at 32 oz/acre. Standard cultural practices of pruning and staking were followed. There were 12 rows 240 foot long divided into 4 replicated blocks of 3 rows each. Each block consisted of 10 treatments assigned in a completely randomized design. An adjuvant, ASPA 80, was added to each spray mixture at the rate of 0.06% v/v except for RH-0345 to which Latron-B-1956 was added at 0.06% v/v. Plants were sprayed weekly except for Biobit alone which was sprayed twice a week at 0.5 lb product/acre. Applications were made with a tractor-drawn hydraulic boom sprayer using a diaphragm pump at 200 psi through two drop lines per row fitted with Albuz@ ATR Yellow nozzles. Spray treatments commenced 29 Mar and continued through 10 May for a total of 7 weeks. Initial spray volume was 46 gal/acre increasing to 65 gal/acre on 5 April and finally to 83 gal/acre 3 May corresponding to the increases in number of nozzles from 2 to 3 to 4 per drop respectively. Plants were evaluated weekly for the presence of whitefly adults, eggs, nymphs, pupae, and parasitized pupae. Relative estimates of adult whitefly numbers were made by striking a black, 9.5” × 13” pie pan coated with an oil/detergent mixture against three plants from each row in every plot and recording the number of adult whiteflies caught. Egg populations were estimated from randomly sampled first expanded trifoliates, one per row (3 per plot). Eggs in 4 cm2 of leaflet were counted with a stereoscopic microscope by placing a 1 cm2 template twice on each side of the midvein. Nymphs were counted in the same way except that the trifoliate sampled came from the 5th, 6th or 7th node from the top. All plants were inspected weekly for symptoms of tomato mottle geminivirus (TMoV), the presence of which was confirmed by nuclear inclusion analysis. On 19 May, all fruit of marketable size was harvested from the best 10 plants per plot. Fruit was culled based on damage from tomato pinworm, other insects, or non-insect causes. Marketable tomatoes were sized to USDA standards on a commercial grading table.

Control of Pepper Weevil with Azadirachtin and Synthetic Insecticides on Bell Pepper, Spring 1994

Abstract Greenhouse raised bell pepper seedlings were transplanted on 7 Feb, 12 inches apart between plants in single rows on raised beds covered with black polyethylene film mulch. Beds were prepared by fumigation with 33/67 chloropicrin/methyl bromide at 220 lbs/acre and fertilized with a bottom mix of 800 lbs/acre of 5-16-8 and a top mix of 1000 lbs/acre of 19-0-30. Rows were 240 feet long on 12 foot centers and watered by subirrigation. Two rows were divided into 4 blocks of 120 feet, each block consisting of 6, 20-ft plots. Plants were sprayed weekly with a fungicide rotating between a mix of 3.0 lbs Kocide DF plus 1.0 lb/acre Maneb 80 W and Bravo applied at 32 oz/acre. Six treatments were assigned to each block in a randomized complete block design with 4 replications. Applications were made on 9 consecutive weeks starting 14 Mar using a 12 tank sprayer equipped with a diaphragm pump powered by a gasoline engine. The sprayer was mounted on a small trailer pulled by a 4-wheel drive Suzuki ATV at 2 MPH. Spray was distributed by a single row boom consisting of 2 side drops with 2 nozzles each and one over the row nozzle for a total of 5 nozzles. Albuz ATR® “red” ceramic tipped nozzles were used at 80 PSI of pump pressure for a delivery rate of 35 gal/acre. An adjuvant, ASPA 80® (Amway Corp.), was added to treatments containing Lorsban, Vydate and Karate at 0.05% v/v and NeemGuard® at 0.14% v/v for the Azadirachtin 4.5%. Following a pretreatment count which yielded an average of 0.13 weevils per 10 plant sample per block, adult weevils were counted weekly on 10 randomly selected plants per plot and bud and fruit drop caused by weevils was evaluated. Aphid infestations on these plants were evaluated by visually rating on a scale of 1 to 5 beginning 5 Apr. Aphid parasitism was evaluated beginning on 25 Apr by counting mummies and nonparasitized apterous aphids from 9 leaves per plot treated with Lorsban and control. Ten plants from each plot were harvested and graded for marketability on 9 May. Nonmarketable fruit was further graded into 3 categories based on type of damage.

Control of Beet Armyworm and Southern Armyworm with Biological Insecticides on Bell Pepperfall 1993

Abstract Seedlings of “Jupiter” bell peppers were transplanted on 1 Oct, 12 inches apart in single rows on raised beds covered with whitefaced polyethylene mulch and sub-surface irrigated. Beds had been prepared by fumigation with chloropicrin methyl bromide 33/67% 220 lbs/acre and fertilized with a bottom mix of 800 lbs/acre of 5-16-8 and a top mix of 1000 lbs/acre of 19-0-30. The plants were sprayed weekly with a fungicide mix of 3.0 lbs Kocide DF and 1.0 lb/acre Maneb 80 W/acre. Four 240-foot rows on 12 foot centers were used, each divided into 7 plots 33 feet long with 18 inches between plots. Six treatments and an unsprayed check were randomly assigned to each row giving 4 replications. Treatments were applied weekly starting 22 Oct following verification of pest infestation. An adjuvant, ASPA 80®, was added to each spray tank at the rate of 3 oz/100 gallon of mix. Applications were made using a 12 tank sprayer mounted on a small trailer and drawn by a 4-wheel drive Suzuki ATV equipped with a diaphragm pump operating at 80 lb/in2 powered by a gasoline engine. Spray was delivered through a single row boom utilizing 3 drops, two on the side carrying 1 or 2 Albuz ATR® “red” ceramic tipped nozzles each depending on plant size and one in the middle carrying a single nozzle for a maximum delivery rate of 35 gpa. Weekly sampling began 21 Oct (pre-treatment) and was initiated from a random start 3-5 plants from the end and continued with every other plant until 8 were sampled. Number and size of the larvae were noted and percent leaf damage to 3 leaf-size categories was estimated. Plants for harvest were selected as above and fruit of marketable size and age was harvested on 16 Dec and again on 23 Dec from the same plants. Number and weight in pounds of marketable peppers were recorded for each plot. Number and weights of culls were recorded in two separate categories: insect damaged and not insect damaged. A small number of culls from pepper weevil damage, noted during the 23 Dec harvest, was included in the general insect-damage category. Data on total numbers of beet armyworm, southern armyworm and leaf damage were subjected to an analysis of variance followed by Duncan’s multiple range test in the event of a significant F value.

Insecticidal Control of Fall Armyworm in Florida Sweet Corn, 1992

Abstract Six raised beds on 6 ft centers prepared on 17 Aug included a fertilizer bottom mix of 1000 lbs/acre of 5-16-8 and 800 lbs/acre of 19-0-19 placed in a central band at bedding. Beds were fumigated with 220 lbs/acre of methyl bromide injected every 5 inches across the bed width and sealed immediately with white-faced, black polyethylene. On 5 Oct, two seeds per hole of the cultivar ‘Florida Staysweet’ were planted in two rows 10 inches apart in the center of each bed and later thinned to one plant per space. Manzate 200 was applied weekly with a plot sprayer at 100 psi to prevent leaf blight and rust. Each of two sets of 3, 240 ft rows was divided into two blocks, 50 ft long, with 100 row ft between blocks. Each row was randomly assigned one of 2 treatments or a control water-treatment in a RCB design. Spray applications were made weekly over 8 weeks beginning 30 Oct using a CO2 pressurized backpack sprayer manufactured by Weed Systems, Inc., Gainesville FL. At an operating pressure of 40 psi, the first 5 applications were calibrated at a rate of 30 gpa and the last 3 at 45 gpa. The surfactant, APSA-80 (80% Alkyl Aryl Alkoxylate) was added at the rate of 0.3% to the Larvin application. Armyworm counts and damage ratings were made one day prior to the first treatment and weekly thereafter by examining the whorl and the next 2 adjacent leaves before tasseling and all ears thereafter. The following numerical ranking system was used for damage ratings: 0: no damage, 1: windowing to 10%, 2: 11-30%, 3: 31-40%, 4: 41-50%, and 5: greater than 50%. Larvae observed during field evaluations were recorded. Plots were harvested on 21 Dec and 7 Jan. All the mature ears were collected and counted and weighed. The number of damaged ears was noted and ears weighed.

Control of Adult Sweetpotato Whitefly (SPWF) and Tomato Mottle Geminivirus (TMOV) Transmission on Staked Tomato, Spring, 1992

Abstract Raised beds 3 ft wide on 6 ft centers were fertilized with a bottom mix of 508 lbs/acre of 5-16-8 NPK and a top mix of 952 lbs/acre 19-0-30, fumigated with Vapam (37% metham-sodium) at the rate of 40 gal/acre, and covered immediately with black polyethylene 3 weeks prior to setting transplants at 20 inch spacing on 23 Mar. Plots were inoculated with TMoV by transplanting 2 infected plants into the center of each middle row. Plants were staked, tied and pruned of suckers 3 times and weekly maintenance sprays of Manzate 200 (1.5 lb/acre), Tri-basic Copper (3 lb/acre), Bravo (2 pts/acre), and Dipel (1 lb/acre), were applied to control diseases and lepidopterous pests. Experimental design was a randomized complete block with 12 treatments and 4 replications. Plots were 26 ft long, 3 rows wide, separated at either end by a 4 ft buffer, and oriented 6 across and 2 deep in blocks running across the field from north to south. No significant block effects were observed. Bay NTN-33893 was applied only once with planting water as a drench. Weekly foliar applications began 24 Apr using a 3-row tractor-drawn sprayer fitted with 4 drop nozzles per row (3 sprays), or 6 drop nozzles per row (4 sprays) delivering 63.7 or 95.5 gpa respectively. Nozzles were equipped with Albuz ATR Red ceramic tips having an average output of 0.61 gal/min each at the 200 psi operating pressure. Mixture concentrations were adjusted to deliver the same amount of AI for each treatment throughout the trial. All water used for applications came from the same source and alkalinity was adjusted by adding 0.18 ml of concentrated H2S04 per gallon prior to adding trial material. The surfactant Triton B1956 was added to the tank mix of Azatin at the rate of 20 oz/100 gal. Adult SPWF were sampled with yellow sticky cards measuring 4 × 4 cm stapled back-to-back on a garden stake and placed 20 cm above soil level with card faces perpendicular to the row in a vertical plane in the center of the center row in each subplot for 24 h beginning 24 h post-treatment. Additional adult counts were made 24 h after applications by striking 5 randomly selected plants per subplot over a 31 × 20 cm teflonlined bake pan coated with a thin layer of vegetable oil and dish detergent, 16:1. Plots were inspected for TMoV and flagged a different color by date on a weekly basis for the duration of the trial.

Suppression of Adult Sweetpotato Whitefly (SPWF) and Spread of Tomato Mottle Geminivirus (TMOV) in Staked Tomato, Spring, 1993

Abstract Greenhouse grown seedlings were transplanted into sandy soil on 8 Mar into single rows on raised beds 36 inches wide on 6 ft centers and subsurface irrigated. Beds were fertilized with a bottom mix of 5-16-8 at 508 lb/acre and top mix of 19-0-30 in 2 bands 9 inches from centerline at 952 lbs/acre, fumigated with 300 lb/acre of 66% methyl bromide and 33% chloropicrin and covered with white-faced polyethylene mulch. Crop was sprayed weekly with Manzate 200 Df at 24 oz/acre and Kocide 100 DF at 3 lb/acre for disease control. Experimental design was randomized complete block with 4 replications, each 3 rows wide by 240 ft long, divided into 10 plots 24 ft long for 9 treatments and an unsprayed check. Spray applications from 6 Apr to 21 May were made with a tractor-mounted hydraulic boom sprayer driven by a diaphragm pump and fitted with four drop lines. Albuz ATR Lilac nozzles were used for the application of JMS Stylet oil at 400 psi (2 times per week) and Albuz ATR Red nozzles at 200 psi for all other treatments (once per week except for New Day detergent at 2 times per week). TMoV-symptomatic greenhouse raised tomato plants that had been exposed to infected whitefly were interplanted into each row of each plot on 12 Mar. An adjacent field of fall-planted collards provided additional whiteflies. Whiteflies were sampled by placing an oil/detergent coated black 10 × 13 inch aluminum pie pan under the plant and striking the plant to dislodge the whiteflies. Nine plants were sampled weekly 24 h after each spray in each plot (3 in each row) through 28 Apr and 3 plants per plot (1 per row) were sampled subsequently.

Control of Sweetpotato Whitefly and Leafminers on Staked Tomato with Insecticide, Soap, and Oil Sprays

Abstract FALL, 1990: Raised beds 36" wide on 6 ft centers were prepared 3 wks before planting in sandy soil at the Southwest Florida Research and Education Center in Immokalee. Fertilizer was applied as a bottom mix before beds were formed (508 lbs/acre of 5-16-8) and as a top mix (952 lbs/acre of 19-0-30) at bed formation in two bands 9" from center. Beds were fumigated at formation with Vapam (37% metham-sodium) at a rate of 30 gal/acre. The Vapam was mixed at a ratio of 3:2 with water and applied with injectors spaced 5" apart across the bed. Immediately after fumigation the beds were covered with whiteface black polyethylene film. Tomato transplants were set 20" apart on 4 Sep. The experimental design was a randomized complete block with 12 treatments and 4 replications. Plots were 3 rows wide, 20 ft long and separated by 40". Treatment applications began 9 Oct and continued weekly until harvest using a tractor mounted boom sprayer with 4 drop lines holding a maximum of 24 nozzles fitted with Albuz ceramic hollow cone tips (ATR brown delivering ca. 0.26 gal/min @ 400 psi). Manzate 200 (1.5 lb/acre) and Tri-Basic Copper (3 lb/acre) were applied weekly for disease control with the same sprayer at 150 psi except that T-Jet hollow cone nozzles with TLX-3 80° tips were used. Whitefly immatures were counted at two week intervals on the terminal trifoliate of the 6th or 7th leaf from the top of 3 randomly selected plants per plot. The number of leafminer stings and mines and the numbers of dead and parasitized leafminers on the trifoliate were also noted. Adult whiteflies were sampled on alternate weeks by counting the number found after carefully inverting the 3rd leaf from the top of 3 randomly chosen plants per plot. Plants affected by geminivirus were marked as symptoms appeared. All fruit of marketable size were picked and graded from 10 randomly selected healthy plants per plot on 27 Nov and 17 Dec. Culls were removed and the remaining fruit separated into medium, large, and extra-large categories with a mechanical grader. Dollar value was estimated on the basis of $5.00/25 lb box for medium fruit, $6.00 for large fruit, and $8.00 for extra-large fruit. A split plot analysis of variance was used with treatments as whole plots and sample dates as subplots.

Technological and ecological problems limiting the production of freshwater and marine fishes in Latin America.

Most of Latin America, with the exception of northern Mexico, Chile, Argentina, Uruguay, and the southern tip of Brazil, is located between the Tropic of Cancer and the Tropic of Capricorn. The tropical oceans have been considered to be less productive than those of the Temperate Zone because of certain environmental factors. The principal factor is the presence of a permanent thermocline in tropical waters. Surface waters are warmer throughout the year and the temperature of the water decreases gradually with increasing depth until reaching the thermocline, a zone of rapid decrease in temperature with moderate increase in depth, which, in effect, separates the colder and denser lower water mass from the warmer and less dense waters above. In temperate waters, the thermocline forms during the summer months; but during the cold season, the surface waters cool down and sink because of their increased density until the temperature in the water column becomes uniform and the thermocline disappears. Because the water column has a uniform temperature and is of equal density, surface waters and bottom waters mix, bringing to the surface nutrient-rich waters from the bottom layers. This process is called overturn, and provides a nutrient-rich environment for the phytoplankton to grow in during the following warm season (1,2).

Notes on the biology ofProtohydra leuckartigreef (Hydroidea, protohydridae)

Abstract The solitary polyp Protohydra leuckarti Greef is extremely common in Danish estuaries and lagoons. It may be found on several kinds of substratum but seems to prefer mixed bottom in shallow water. P. leuckarti is normally red due to carotenoids from devoured copepods. Experiments showed that the polyp is able to catch all stages of harpacticoids, nematodes and small chironornids, Halacarids and ostracods were not readily accepted and hardly play any role as food animals in nature. The transversal division is the normal way of reproduction. The process lasts 12–24 hours at 20° C and about nine days at 4–5° C. Fed with one adult harpacticoid (Tachidius sp.) per day P. leuckarti would divide every four days. Protohydra seems to have a resting period in the autumn. Sexual reproduction was found in autumn animals and in some winter animals casually exposed to drastically changing temperatures and periods of starvation. The ripening of the gonads lasted 28 days. The eggs measured 310 × 160 µ. They were expelled but did not develop. The mother animals do not die after spawning, but in some cases they perform abnormal divisions, and it seems probable that a report on budding in this species is due to a misinterpretation of this phenomenon.