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Chlorantraniliprole susceptibility was determined in diet-incorporation bioassays for six fall armyworm, Spodoptera frugiperda (J. E. Smith), populations feeding on sweet corn, Zea mays L., in southern Florida between 2017 and 2019. The LC50 and LC90 values of these populations estimated using probit analyses ranged from 0.022 to 0.084 ppm and 0.112 to 0.471 ppm, respectively. Thus, susceptibility levels among the six field populations varied, but to a relatively small extent, with approximately fourfold differences in LC50 and LC90 values between the most and least susceptible populations. These field populations were all less susceptible than a reference population maintained in the laboratory without prior exposure to chlorantraniliprole, with RR50 values between 5.3 and 20.1 and RR90 values between 14.3 and 60.3. These results suggest reduced chlorantraniliprole susceptibility in S. frugiperda populations collected in Florida sweet corn relative to a reference laboratory population. However, field experiments in 2017 and 2019 showed that foliar applications of chlorantraniliprole reduced S. frugiperda injury and infestations to levels comparable to or lower than applications of indoxacarb, novaluron, or spinetoram. This study does not provide evidence of practical resistance to chlorantraniliprole in S. frugiperda infesting Florida sweet corn fields.

Chapter 15 of the Vegetable Production Handbook.

Chapter 17 of the Vegetable Production Handbook.

Chapter 10 of the Vegetable Production Handbook.

Chapter 9 of the Vegetable Production Handbook.

This chapter covers beet, radish, carrot, sweetpotato, cassava, taro, and malanga production.

This chapter covers production of celery, okra, and parsley.

This chapter covers lettuce, endive, escarole, and spinach cultivation.

The sugarcane aphid, Melanaphis sacchari (Zehntner), has emerged as a serious pest of sorghum in the United States. Field trials were conducted in Louisiana and South Carolina in 2016–2018 to investigate its population characteristics and distribution patterns in relation to four sample unit sizes (three circular and one leaf based). Sugarcane aphid populations usually progressed through a phase of rapid rise followed by a phase of rapid decline within a span of 5–6 wk, with peak density determined by sorghum cultivars and climatic conditions. Peak population densities for susceptible cultivars were 1.9–14.9× that for resistant cultivars on a per plant basis. Melanaphis sacchari tended to concentrate on the lower green leaf nodes early in the infestation, with the distribution shifting toward higher green leaf nodes as the infestation progressed. Aphid densities per cm2 at the basal and middle sections were about twice as high as at the distal section of leaves. The proportions of infested sample units were fitted to the Wilson–Room binomial model that incorporates the effect of density on clumping pattern. For a specific sample unit size, clumping patterns were similar across cultivars, years, and leaf positions, but varied across infestation stages. For a fixed aphid density per sample unit, the proportion of infested sample units decreased with increasing sample unit size. For a fixed aphid density per cm2, proportion infested increased with increasing sample unit size, indicating less clumping with a larger sample unit size. Field sampling time and efficiency between samplers were quantified.

Sugarcane yellow leaf virus (SCYLV), the causal agent of yellow leaf disease, naturally infects at least three plant species in Florida: sugarcane (Saccharum spp.), the weed Columbus grass (Sorghum almum) and cultivated sorghum (S. bicolor). All three hosts are also colonized by the sugarcane aphid (Melanaphis sacchari), the main vector of SCYLV worldwide. To understand the high incidence of SCYLV observed in sugarcane commercial fields and in germplasm collections, we investigated the transmission efficiency of SCYLV from sugarcane and Columbus grass to sugarcane using the sugarcane aphid and a spider mite (Oligonychus grypus) that also tested positive for SCYLV in Florida. Healthy and SCYLV-infected leaf pieces of sugarcane and Columbus grass carrying viruliferous aphids or spider mites were transferred to virus-free plants of the yellow leaf susceptible sugarcane cultivar CP96-1252. Three- and 6-months post inoculation, the 108 aphid-inoculated plants of Columbus grass and the 90 mite-inoculated plants of sugarcane tested negative for SCYLV by tissue blot immunoassay (TBIA) or reverse transcription polymerase chain reaction (RT-PCR). Similar results were obtained for 162 aphid-inoculated plants of sugarcane, except for two plants that tested positive for SCYLV by TBIA and RT-PCR. In two field experiments planted with SCYLV-free and virus-infected sugarcane (cultivar CP96-1252), only 18–28% of healthy plants became infected during a 24- to 28-month period. SCYLV prevalence in these field experiments did not differ between aphicide treated and untreated plots. Incidence of M. sacchari haplotypes in the Everglades agricultural area also indicated that the predominant haplotype that is currently colonizing sugarcane was not a vector of SCYLV in Florida. Lack of virus transmission by the spider mite suggested that this arthropod only acquired the virus when feeding on infected plants but was unable to transmit SCYLV. The current vector of SCYLV in Florida remains to be identified.

A study was conducted in Florida to determine sugarcane borer, Diatraea saccharalis (F.), injury and infestation levels in sugarcane (Saccharum spp. hybrids), D. saccharalis parasitism rates, and ant foraging activity in 32 commercial fields as affected by soil type (shallow organic vs deep organic vs mineral). In 2017 and 2018, each field was sampled four times during the summer for D. saccharalis by inspecting 100 sugarcane stalks and for foraging ants using plastic tubes baited with hot dog at 12 locations. One non-parasitized D. saccharalis larva was collected in 2017 and in 2018 out of 12,100 and 12,600 stalks sampled, respectively. Additional sampling of 50 stalks per field in October showed that 0.6% (2017) and 0.1% (2018) of the sugarcane stalks had bored internodes, and one Cotesia flavipes (Cameron) (Hymenoptera: Braconidae) cocoon mass was observed. Seven ant species foraged in sugarcane fields, including the red imported fire ant, Solenopsis invicta Buren, which was the most abundant ant. Solenopsis invicta was not affected by soil type; however, sugarcane fields on shallow organic soils might represent a more suitable environment. The third most abundant foraging ant, Nylanderia bourbonica (Forel), was more abundant in mineral soil fields than in shallow and deep organic soil fields. Results suggest that D. saccharalis population levels in Florida sugarcane are extremely low under current production conditions regardless of soil type. In addition, the observation of C. flavipes, S. invicta, and six other ant species suggest that biological control contributes to these low D. saccharalis population levels.

The West Indian canefly, Saccharosydne saccharivora (Westwood) (Hemiptera: Delphacidae), is a sporadic pest of sugarcane in Louisiana which has recently emerged as a more consistent threat with outbreaks occurring in 2012, 2016, 2017, and 2019. Surveys of commercial fields in 2016 revealed that S. saccharivora infestations were present throughout Louisiana sugarcane and populations peaked in mid-June before declining. High minimum winter temperatures are generally associated with S. saccharivora outbreaks. Six insecticide evaluations demonstrated effective control with several insecticides including λ-cyhalothrin, flupyradifurone, acetamiprid, and imidacloprid. In five of the six insecticide trials, S. saccharivora infestations had substantially declined by 21 d after treatment. Effects of insecticidal control of S. saccharivora on sugar yields were detected in one of four small plot trials in which yield data were collected. Linear regression revealed S. saccharivora cumulative insect days in a grid sampling study were inversely associated with sugar yields. Results from these collective experiments suggest impacts on sugar yields are influenced by pest density and infestation duration. Differences were detected in numbers of S. saccharivora nymphs and adults as well as sooty mold coverage among commercial sugarcane cultivars with more than twofold increases in the most susceptible compared to resistant cultivars. The research presented herein documents the impact of S. saccharivora to Louisiana sugarcane and provides important ground work for developing effective pest management strategies. Future research efforts should aim to identify ecological factors influencing population dynamics, varietal preferences, and economic thresholds.

The sugarcane borer, Diatraea saccharalis (F.), rice stalk borer, Chilo plejadellus Zincken, and Mexican rice borer, Eoreuma loftini (Dyar), are stem borers (Lepidoptera: Crambidae) that infest rice (Oryza sativa L.) in the southern United States. A 2-yr study was conducted to determine stem borer injury, infestation, and parasitism levels in Florida. Thirty commercial rice fields were selected during the 2017 and 2018 growing seasons throughout the rice production region in southern Florida. Sampling for stem borer injury and infestations was conducted in each field between the milk and early maturation stages by observing plants at 10 locations, with three 1-m2 quadrats per location. In addition, monitoring for E. loftini adults was conducted using one pheromone trap adjacent to each field. In 2017, the number of rice tillers exhibiting stem borer injury averaged 0.024 tillers/m2 and infestation levels averaged 0.008 stem borers/m2, with only D. saccharalis being observed. In 2018, injury and infestation levels averaged 0.062 injured tillers/m2 and 0.023 D. saccharalis larvae or pupae/m2, respectively. The solitary parasitoid Alabagrus stigma Brullé (Hymenoptera: Braconidae) parasitized 33 and 40% of the collected D. saccharalis in 2017 and 2018, respectively. In addition, pheromone traps did not capture E. loftini adults. This study shows that D. saccharalis infests rice in Florida but at relatively low levels not threatening production and that rice fields are habitats for D. saccharalis parasitoids. This study also suggests that C. plejadellus and E. loftini do not occur in southern Florida.

Fulmekiola serrata (Kobus) was observed infesting sugarcane, Saccharum spp. hybrids, in the United States for the first time in January 2017 in Florida. Field studies were conducted to determine F. serrata infestation levels on popular sugarcane cultivars and to determine the efficacy of foliar insecticide treatments that could be used for management. Cultivar evaluations comparing six and five commercial cultivars representing >46% of the sugarcane production area in Florida were conducted in 2017 and 2018, respectively. Fulmekiola serrata infestation levels did not differ among cultivars in 2017. However, infestation levels on CP 00-1101 were greater than on CP 96-1252 grown on organic soils, and infestation levels on CP 96-1252 were greater than on CPCL 97-2730 grown on mineral soils in 2018. Three insecticide evaluations, two in 2017 and one in 2018, were conducted. The pyrethroid lambda-cyhalothrin, which is registered for use on sugarcane, was consistently associated with the greatest decreases in F. serrata infestation levels. The neonicotinoids imidacloprid and thiamethoxam, as well as the butenolide flupyradifurone, decreased infestation levels but to a lesser extent than did lambda-cyhalothrin. The spinosyn spinetoram was associated with the lowest decreases in F. serrata infestation levels. Our results supported short-term F. serrata management recommendations: Popular Florida sugarcane cultivars should be considered equally susceptible to F. serrata until additional evaluations are conducted and F. serrata outbreaks can be treated with lambda-cyhalothrin when infestations stress the crop beyond acceptable levels.

Melanaphis sacchari (Zehntner) is a major pest of sorghum, Sorghum bicolor (L.) Moench, in the United States and neighboring Caribbean countries including Haiti. Laboratory, greenhouse, and field experiments were conducted to determine the effects of biological insecticides on M. sacchari infesting sorghum. Azadirachtin, pyrethrins, Beauveria bassiana strain GHA, Isaria fumosorosea Apopka strain 97, Chromobacterium subtsugae strain PRAA4-1T, Burkholderia spp. strain A396, and vetiver oil were compared to a conventional insecticide, flupyradifurone. In the laboratory, sorghum leaf discs were sprayed with treatment solutions and subsequently infested with M. sacchari nymphs. In the greenhouse, potted sorghum plants were sprayed with treatment solutions before or after infestation with M. sacchari nymphs. In the field, plots exposed to natural M. sacchari infestations were sprayed with treatment solutions. All insecticide treatments except I. fumosorosea and Burkholderia spp. were associated with 58–100% aphid mortality after 72 h in the laboratory, which was greater than the 20% mortality observed in the non-treated control. In the greenhouse, azadirachtin and pyrethrins were the biological insecticides associated with the lowest aphid infestation levels 7 days after treatment. Flupyradifurone was associated with the greatest mortality in the laboratory and the lowest infestation levels in the greenhouse. In the field, decreases in aphid infestation levels relative to the non-treated control were not observed although flupyradifurone was consistently associated with the lowest infestations. Our results suggest that biological insecticides including azadirachtin, pyrethrins, and B. bassiana could potentially control M. sacchari infestations in sorghum if applied under favorable environmental conditions.

Sugarcane (Saccharum interspecific hybrids) is the main source of sugar in the world. It is grown in more than 90 countries in tropical and subtropical regions. Cultivation techniques and production challenges vary by location (Rott 2017; Rott 2018). This 19-page document discusses characteristics of the sugarcane crop and pests affecting its production in Florida, which is the largest producer of sugarcane in the United States. Written by P. Rott, D. C. Odero, J. M. Beuzelin, R. N. Raid, M. VanWeelden, S. Swanson, and M. Mossler, and published by the UF/IFAS Agronomy Department, revised May 2018. https://edis.ifas.ufl.edu/pi207

The corn wireworm, Melanotus communis (Gyllenhal) (Coleoptera: Elateridae), is an important soil insect pest of Florida sugar cane (Saccharum spp.; Poaceae). The objective of this study was to determine the host plant preference of M. communis adults and larvae to weeds and sugar cane varieties found in Florida sugar cane fields. Three sugar cane varieties, 3 grass weeds, and 3 broadleaf weeds were tested for their attraction to the insects in free choice tests. After a 24 h exposure to whole plant extracts (juices), most adults were found in sugar cane varieties, followed by grass weeds, then broadleaf weeds. After a 48 h exposure to chopped roots in muck soil, most larvae were found in sugar cane varieties, followed by grass weeds, then broadleaf weeds. After a 48 h exposure to chopped roots in sandy soil, most larvae were found in sugar cane varieties, followed by broadleaf weeds, then grass weeds. Our data show that in free choice tests, both M. communis adults and larvae prefer sugar cane over weeds present in Florida sugar cane fields. Resumen El gusano del maiz, Melanotus communis (Gyllenhal) (Coleoptera: Elateridae), es una plaga importante de la cana de azucar (Saccharum spp.; Poaceae) en la Florida. El objetivo de este estudio fue determinar la preferencia de la planta hospedera de los adultos y larvas de M. communis a las malezas y variedades de cana de azucar que se encuentran en los campos de cana de azucar de la Florida. Se probaron tres variedades de cana de azucar, 3 pastos-malezas y 3 malezas de hoja ancha por su atraccion hacia los insectos en pruebas de libre eleccion. Despues de una exposicion de 24 h a extractos de plantas enteras (jugos), la mayoria de los adultos se encontraron en variedades de cana de azucar, seguidos de los pastos-malezas y luego malezas de hoja ancha. Despues de una exposicion de 48 h a las raices cortadas en el suelo de lodo, la mayoria de las larvas se encontraron en variedades de cana de azucar, seguidas de los pastos-malezas y luego las malezas de hoja ancha. Despues de una exposicion de 48 h a las raices picadas en el suelo arenoso, la mayoria de las larvas se encontraron en variedades de cana de azucar, seguidas por los pastos-malezas y luego por las malezas con hojas anchas. Nuestros datos muestran que en las pruebas de libre eleccion, tanto los adultos como las larvas de M. communis prefieren la cana de azucar en lugar de las malezas presentes en los campos de cana de azucar en la Florida. Key Words: wireworms; click beetles; ecology; Saccharum View this article in BioOne https://doi.org/10.1653/024.102.0213

Effects of treatment of rice seeds with an anthranilic diamide, chlorantraniliprole, and a neonicotinoid, thiamethoxam, on egg laying and first instar survival in rice water weevil, Lissorhoptrus oryzophilus Kuschel, were examined under greenhouse conditions. Exposure of adult weevils to rice (6-7 leaf stage) grown from seeds treated with chlorantraniliprole and thiamethoxam resulted in reduction in numbers of eggs and first instars. The low egg numbers by adults exposed to chlorantraniliprole-treated plants was confirmed as a sublethal effect on adults: adult survival was not impacted after 4 d of feeding on foliage from chlorantraniliprole-treated plants but the number of eggs laid by these weevils was reduced when released on untreated plants. Furthermore, a comparison of first instar emergence from chlorantraniliprole-treated plants and from untreated plants infested with weevils previously exposed to this chemical suggested that chlorantraniliprole was also reducing egg or first instar survival. In contrast, adults that fed on foliage from thiamethoxam-treated plants showed increased mortality. Possible sublethal effects of thiamethoxam on the number of eggs laid by adults were investigated by infesting untreated plants with weevils that survived exposure to thiamethoxam via foliar feeding (7 microg active ingredient/seed). Prior exposure to thiamethoxam through adult feeding reduced egg numbers. However, potential larvicidal or ovicidal effects of thiamethoxam seed treatments could not be detected in this study because of low first instar emergence from both thiamethoxam-treated plants and from untreated plants infested with weevils previously exposed to this chemical. These experiments revealed that the two seed treatments accomplish weevil control in different ways.

A three-treatment aerial application insecticide experiment was conducted in five commercial sugarcane, Saccharum spp., fields in south Texas to evaluate the use of pheromone traps for improving chemical control of the Mexican rice borer, Eoreuma loftini (Dyar), in 2009 and 2010. A threshold of 20 moths/trap/wk was used to initiate monitoring for larval infestations. The percentage of stalks with larvae on plant surfaces was directly related to the number of moths trapped. Reductions in borer injury and adult emergence were detected when a threshold of >5% of stalks with larvae present on plant surfaces was used to trigger insecticide applications. Novaluron provided superior control compared with beta-cyfluthrin; novaluron treated plots were associated with a 14% increase in sugar production. A greenhouse experiment investigating establishment and behavior of E. loftini larvae on two phenological stages of stalkborer resistant, HoCP 85-845, and susceptible, HoCP 00-950, sugarcane cultivars determined that more than half of larvae on HoCP 00-950 and > 25% on HoCP 85-845 tunneled inside leaf mid-ribs within 1 d of eclosion, protected therein from biological and chemical control tactics. Exposure time of larvae averaged < 1 wk for all treatments and was shortest on immature HoCP 00-950 and longest on mature HoCP 85-845. This study shows a short window of vulnerability of E. loftini larvae to insecticide applications, and demonstrates the potential utility of pheromone traps for improving insecticide intervention timing such that a single properly timed application may be all that is required.

Sugarcane (Saccharum L.) in Louisiana is colonized by the sugarcane aphid, Melanaphis sacchari (Zehntner), and the yellow sugarcane aphid, Sipha flava (Forbes). Five commercial sugarcane cultivars, ‘LCP 85-384′, ‘HoCP 91-555′, ‘Ho 95-988′, ‘HoCP 96-540′, and ‘L 97-128′, representing >95% of Louisiana's sugarcane-growing area, were assessed under southern Louisiana field conditions for numbers of the two aphid species. Biweekly sampling during 2007 and 2008 growing seasons indicated cultivar and time effects on aphid frequency. Aphid population peaks occurred during June and July and then crashed. M. sacchari was more abundant than S. flava on almost all cultivars and on all sampling dates during both years of the study. HoCP 91-555 was found to be the most resistant compared with the susceptible Ho 95-988 and L 97-128 cultivars. HoCP 91-555 might be useful in areas of high aphid pressure, and as a source of resistance in cultivar development programs.

A field experiment was conducted at the LSU AgCenter Dean Lee Research Station in Alexandria, LA, to evaluate insecticides for management of sweetpotato soil insect pests, including BCB and SCB. In addition to an untreated check, three insecticide treatments were assessed in a RCB design with four blocks and one replicate per block. Plots were three rows wide (38-inch centers) and 35 ft long. A CO2-pressurized backpack sprayer calibrated to …

A study was conducted at the LSU AgCenter Dean Lee Research Station in Alexandria, LA to evaluate insecticides for management of the sugarcane aphid. Six foliar insecticide treatments and an untreated check were assessed in an RCB design with four blocks (one replicate per block). Grain sorghum (Dekalb DKS53-67) was planted on 3 Jun on 38-inch centers at a density of 83,100 seeds per acre. Plots were four rows wide and 35 ft long. Insecticide treatments were applied on 31 Jul after sampling two leaves per plant from 25 randomly selected plants in each block revealed that sugarcane aphid densities had reached 112 aphids per leaf on 30 Jul. A high-clearance self-propelled sprayer with a compressed-air …

The efficacy of insecticides labeled for SCB management in sugarcane was assessed in a field of variety HoCP 96-540 (first stubble) on a commercial farm near Jeanerette, LA. Eight insecticide treatments and an untreated check were evaluated in a RCBD with four blocks and one replicate per block. Plots were 24-ft wide (four 6-ft rows) and 24-ft long separated by 6-ft alleys. Inspection of 300 …