化学防治对绿化带中红火蚁及本地蚂蚁的影响

研究了饵剂、粉剂和灌巢3种不同施药方法对红火蚁的防治效果及对绿化带本地蚂蚁的影响.结果表明:从活动蚁巢和工蚁减退率两项指标来看,粉剂防治绿化带中红火蚁效果快速稳定,可以推广使用;饵剂防治作用较缓慢,处理35d后达到最好的防治效果;而灌巢虽然能在短期内有效地减少活动蚁巢数量,但对工蚁的防效较差,总体上不如粉剂和饵剂.此外,饵剂和粉剂都能显著降低绿化带本地蚂蚁的种类和数量,灌巢则对本地蚂蚁的影响较小.通过分析施药前后各处理区的蚂蚁类群多样性指数、均匀度指数和优势度指数的变化,可以看出各处理区的蚂蚁类群多样性指数,均匀度指数和优势度指数与CK相比,都呈下降趋势,说明化学防治能有效压制红火蚁的数量,但同时也严重影响着本地蚂蚁.     

高效氯氟氰菊酯微囊悬浮剂与二阶段法对红火蚁的田间防治效果评价

研究了高效氯氟氰菊酯微囊悬浮剂与二阶段法对红火蚁的田间防治效果。结果表明,0.25 g/L高效氯氟氰菊酯微囊悬浮剂施药后击倒红火蚁迅速,14 d后活动蚁巢减退率、工蚁减退率、蚁巢级别降低率、综合防治效果均达到100%。使用0.045%茚虫威饵剂搭配0.25 g/L高效氯氟氰菊酯微囊悬浮剂的二阶段法,5 d后红火蚁的活动蚁巢和工蚁数量均显著下降,14 d后活动蚁巢减退率、工蚁减退率、蚁巢级别降低率、综合防治效果均达到100%。结果表明,0.25 g/L高效氯氟氰菊酯微囊悬浮剂对红火蚁具有高效的控制作用,在实际使用时可根据防治面积的大小选择单独灌巢还是配合饵剂的二阶段法。     

药剂灌巢剂量对红火蚁蚁巢迁移的影响

为了明确药剂灌巢剂量对红火蚁蚁巢迁移的影响。本研究利用不同剂量的锐劲特药液对红火蚁进行灌巢处理,在野外条件下观察了药剂灌巢后红火蚁蚁巢的迁移情况。结果表明:(1)当药液量与蚁巢体积的比例低于1.6时,会出现蚁巢迁移,药液量较大时,灌巢防治红火蚁可取得较好的防效;(2)随着灌巢药液量的增加,新蚁巢出现的个数明显减少,出现比例明显降低,新蚁巢的体积明显减小;(3)随着灌巢药液量的增加,新蚁巢出现的时间会延迟,处理药液量为2.5 L时,新蚁巢一般出现在1-3 d内,而药液量增加后,新蚁巢一般在3-5 d出现;(4)药剂灌巢防治后,红火蚁会在距处理蚁巢1-7 m范围内建立新蚁巢,不同药液量处理之间没有明显差异,新蚁巢出现的位置没有明显的方位取向。为避免灌巢不彻底导致蚁巢迁移,应保证灌巢用药量充足,推荐药液量为蚁巢体积的2倍以上。     

氟虫腈防治红火蚁对绿地蚂蚁群落多样性的影响

【目的】研究饵剂点播、饵剂撒播、药剂灌巢3种不同处理方法防治红火蚁Solenopsis invicta对绿地蚂蚁群落多样性的影响,为绿地红火蚁的防治与本地蚂蚁的保护利用提供科学依据。【方法】在广州市南沙区绿化地,采用掉落式陷阱法调查研究绿地的蚂蚁群落结构,并对比分析饵剂点播、饵剂撒播、药剂灌巢对蚂蚁群落多样性的影响。【结果】(1)在饵剂点播、饵剂撒播、药剂灌巢和对照4个处理区中共采集到44 361头蚂蚁,分属于8个亚科,33个种;(2)防治前后各处理区之间的蚂蚁种类数变化不大,但其蚂蚁数量却存在明显差异;(3)防治前不同处理类型之间的蚂蚁群落多样性指数无显著差异,防治后仅有药剂灌巢区的蚂蚁多样性指数显著升高。【结论】化学防治可以改变蚂蚁的群落结构,药剂灌巢的处理方法可以显著降低蚂蚁的种群数量,并显著提高其处理区的蚂蚁多样性,适用于城市绿地的红火蚁防控。     

红火蚁防控药剂使用后对草坪节肢动物群落的影响

【目的】化学防治是目前控制红火蚁Solenopsis invicta为害的最有效的方法。化学药剂在对红火蚁起到良好防效时,也会对发生区的其他节肢动物群落造成一定的影响。本文研究了红火蚁常用防治药剂施用后对红火蚁典型发生区域-草坪生境中节肢动物群落的影响。【方法】使用网捕法和陷阱取样法调查处理和对照区的节肢动物。【结果】调查表明,施用推荐剂量的0.015%多杀菌素饵剂35 g/巢、0.045%茚虫威饵剂5 g/巢、0.096%氟虫腈粉剂30 g/巢和4.5%高效氯氰菊酯乳油2 000倍液后,对草坪上节肢动物群落产生不同的影响。研究发现,在农药处理后,各处理区节肢动物的Shannon-Wiener多样性指数得到不同程度的提高,在处理后45 d后,多杀菌素饵剂、茚虫威饵剂、氟虫腈粉剂和高效氯氰菊酯乳油处理区的Shannon-Wiener多样性指数分别为2.1、2.0、1.8和2.1,显著高于对照区的1.5。通过主成份分析得到施用30 g/巢0.096%氟虫腈粉剂和2 000倍液的高效氯氰菊酯乳油灌巢对节肢动物群落恢复产生一定的负面影响,即造成节肢动物群落中的非靶标生物的死亡。【结果】红火蚁种群在被药剂压制后,各药剂处理区中的生物多样性得到不同程度的恢复;35 g/巢的0.015%多杀菌素饵剂和5 g/巢的0.045%茚虫威饵剂对节肢动物群落相对安全,节肢动物群落相比对照区在防治后表现为物种相对丰富和群落结构稳定。     

防治甘草萤叶甲生物源农药筛选及其对生物多样性的影响

为了筛选出防治甘草萤叶甲Diorhbda tarsalis Weise的生物药剂,采用多种生物源药剂,通过室内、田间试验,进行综合分析。室内毒力测定结果表明,甘草萤叶甲对0.5%黎芦碱SL的敏感性最高,LD50为0.139mg/L,0.3%印楝素EC、L2、1%苦参碱SL、L1依次递减,LD50分别为0.457,1.352,2.014和2.251mg/L,均高于其他药剂。田间防效结果表明,黎芦碱药后21d对甘草萤叶甲的防效最高,为100%,苦参碱、印楝素次之,均为86.67%,L2、L1的分别为66.67%和40%;对非靶标害虫小绿叶蝉也有较好的控制作用,药后21d防效L1较低,为56.67%,其他防效均高于68.89%;对田间天敌多异瓢虫和中华草蛉的安全性,除黎芦碱外,印楝素、苦参碱、L2、L1均较好,药后21d校正虫口减退率最高为57.14%;另外,苦参碱药后各期生物多样性指数平均最高,为2.93,印楝素次之,为2.88,藜芦碱、L1、L2依次递减,分别为2.45,2.43和2.07。因此,印楝素、苦参碱是防治甘草萤叶甲的理想药剂。     

不同剂量灭蚁威饵剂对红火蚁的田间防治效果评价

【目标】明确红火蚁Solenopsis invicta Buren毒饵最佳使用剂量有助于有效控制红火蚁、降低防治成本和保护生态安全。【方法】采用活动蚁巢减退率、工蚁减退率与蚁群级别降低率综合评价了单蚁巢点施不同剂量灭蚁威饵剂对红火蚁的田间防治效果。【结果】结果表明,地表有效体积大小一致的蚁巢实施25、20、15、10、5 g饵剂处理25 d后,对应的活动蚁巢减退率分别为80%、90%、100%、90%、90%,工蚁减退率分别为100%、100%、100%、98.1%、99.2%,蚁群级别降低率为86.7%、90%、100%、80%、76.7%。同时,在最适投饵量基础上,针对不同地表有效体积大小的蚁巢投施相应饵剂量,综合防治效果达94%以上。【结论】上述结果可见,对蚁巢地表有效体积大小0.066 m~3的蚁巢施用15 g灭蚁威饵剂能起到最佳的防治效果,而且每0.03 m~3蚁巢地表有效体积大小相对应的饵剂量为5 g。     

红火蚁对新入侵龙眼园和荒草地蚂蚁类群多样性的影响

于2007年7月至2008年2月期间在增城龙眼园及周边的荒草地人工移殖1蚁巢及10蚁巢红火蚁,并采用陷阱法和诱饵诱集法调查研究红火蚁对新入侵龙眼园区和荒草地区蚂蚁类群多样性的影响。结果表明,在荫蔽、少干扰的龙眼园和杂草茂密、少干扰的未割草区,红火蚁难以成功定殖,对这两种生境蚂蚁类群的多样性几乎没有影响;在红火蚁成功定殖的1蚁巢割草区和10蚁巢割草区,红火蚁以这两种密度入侵对蚂蚁类群多样性的影响程度不同。在1蚁巢割草区,红火蚁入侵后5个月期间,由于其数量占蚂蚁个体总数的比例很少,对蚂蚁类群多样性的影响很小;在红火蚁成功定殖5个月后,第6—7个月其工蚁所占比例增加,蚂蚁类群个体数和优势度下降,多样性和均匀度增加;第8—9个月其工蚁所占比例继续增加,而蚂蚁个体数、多样性和均匀度下降,优势度增加。在10蚁巢割草区,红火蚁入侵后,蚂蚁类群个体数、多样性和均匀度下降,优势度增加。红火蚁入侵对1蚁巢割草区和10蚁巢割草区蚂蚁物种数的影响较小。     

几种杀虫剂对热带雨林生态区红火蚁蚁巢和工蚁的灭杀效果

为筛选出适用于云南热带雨林生态区的红火蚁Solenopsis invicta Buren防治药剂,通过7种杀虫剂对红火蚁蚁巢田间灭除效果试验测定。结果表明,20%多杀霉素悬浮剂（SC）、30%螺虫·噻虫嗪悬浮剂（SC）、70%吡虫啉可湿性粉剂（WP）、10%溴虫氟苯双酰胺悬浮剂（SC）和1%联苯·噻虫嗪颗粒剂（GR）对红火蚁蚁巢处理效果较好,药后1 d和10 d虫口减退率分别在95%和90%以上。其中10%溴虫氟苯双酰胺SC和1%联苯·噻虫嗪GR可作为红火蚁巢点处置的首选药剂;0.05%茚虫威饵剂（EB）速效性差,但药后10 d虫口减退率上升到86.8%。1.8%阿维菌素乳油（EC）药后1 d和10 d虫口减退率分别为89.3%和81%。这2种药剂可与前5种药剂交替使用。     

曲靖市沾益区红火蚁发生规律研究

红火蚁Solenopsis invicta Buren是国际最具危险性的入侵性物种之一,传播扩散速度快、适生能力强。云南由于其独特的地理和气候环境,给红火蚁的入侵和发生提供了丰富的栖息环境和食物。本研究对云南高海拔冷凉区域人工草坪条件下红火蚁婚飞有翅蚁、工蚁活动规律,以及蚁巢变化规律进行了系统的调查研究。结果表明,在人工草坪条件下,红火蚁婚飞活动主要发生在每年的5-8月,6月初和8月初为婚飞生殖蚁发生高峰期,婚飞生殖蚁数量分别达到390.33头/1 000 m^2和523.33头/1 000 m^2,分别占到全年婚飞生殖蚁总量的25.19%和33.77%;诱集工蚁数量在6月下旬-7月上旬、8月下旬-9月下旬达到两个高峰,合计诱集数量分别为634.66头/1 000 m^2和1 636.00头/1 000 m^2,分别占到全年诱集工蚁总量的44.59%和17.30%;新增蚁巢数量在6月1日-7月1日、8月16日、9月15日-12月16日、次年3月14日-4月15日为4个增长阶段,新增蚁巢数量分别为9.66个/1 000 m^2、4.33个/1 000 m^2、5.67个/1 000 m^2、2.00个/1 000 m^2、分别占到全年新增蚁巢总数的44.62%、20.00%、26.15%、9.23%。综合婚飞年度规律、全年诱集工蚁数量、活动蚁巢数量和新增蚁巢数量方面的结果,人工草坪条件下,6-9月为红火蚁的活动发生高峰期,结合当地的实际情况,建议每年的4-6月和8-9月采用毒饵与粉剂相结合的方式进行防治,在12月份采用低毒农药灌巢进行防治。     

Susceptibility and behavioral response of red imported fire ant (Hymenoptera: Formicidae) to selected entomogenous nematodes (Rhabditida: Steinernematidae & Heterorhabditidae).

Pathogenicity of infective juveniles of selected Steinernema spp. and Heterorhabditis spp. toward developing and reproductive stages of the red imported fire ant, Solenopsis invicta Buren, was tested under laboratory conditions. At 10(3)-10(5) infective juveniles per Petri dish, mortality of reproductive larvae, pupae, and alates ranged from 28 to 100% at higher doses after 96 h at 23-25 degrees C. Steinernema carpocapsae All was the most consistent species tested; this nematode caused mortality of fire ant larvae, pupae, and alates of 82-94, 64-96, and 38-99%, respectively. Although not susceptible to nematode infection, worker ants vigorously preened nematodes from brood, alates, and themselves. In a field study, S. carpocapsae (5 x 10(6) and 2 x 10(6) drench, 2 x 10(6) infective juvenile infection) was applied to active fire ant mounds in 3.8-liter suspensions. Hydramethylnon (75 ml), a water drench, a water injection, and untreated fire ant mounds were marked and treated. Overall activity in mounds treated with nematodes of hydramethylnon ranged from 40 to 48%. Satellite mound activity accounted for 32-44% of overall activity in mounds treated with nematodes 2 wk after treatment. However, 6 wk after treatment, activity in mounds treated with hydramethylnon was 44%; activity of mounds treated with nematodes ranged from 52 to 80%. Satellite mound activity accounted for 0-24% of overall activity. Whereas a soil drench of S. carpocapsae showed potential as a control method for the red imported fire ant, colony relocation after nematode treatment could limit overall efficacy unless application techniques are developed to overcome or take advantage of the movement.     

Thermoregulatory brood transport in the fire ant, <Emphasis Type="Italic">Solenopsis invicta</Emphasis>

Nest structure in ants is often designed to optimize the colony’s ability to thermoregulate, and this specialization is most highly developed in mound-building ant species. Solenopsis invicta invest a large amount of energy in building mounds and transporting their brood up and down in their nests as a means of thermoregulation. Because few ant species build true mounds, we wanted to determine the effectiveness of these mounds in harvesting solar heat as well as to distinguish what factors (temperature vs. circadian rhythm) govern where fire ants place their brood in the mound and when they place it. We measured temperature patterns in the mound over several days at different depths and under different conditions (under direct sunlight or shade), and then conducted a series of field experiments to manipulate the orientation and time of heating. On cool mornings in spring or fall, surface temperatures of the mound rise at the fastest rate on the side receiving the most direct sunlight (usually the south side). This heating causes a temperature gradient through different depths in the mound, and shows little difference from outside ground temperature at a depth greater than ~40 cm inside the nest. In the morning, fire ants move their brood up into the mound on the side most directly heated, and when temperatures exceed optimal (~32°C) they move their brood down the temperature gradient to lower depths in the nest. In addition to this, mound temperature does not only increase due to direct sunlight, but temperature also increases higher than ground temperatures when the mound is in the shade due to its low specific heat. Experiments in which sunlight was mirrored to the normally shaded side of the mound, or when mounds were heated at night, revealed that S. invicta primarily track temperature patterns and do not rely on behavioral habits or circadian rhythms for the thermoregulatory transport of their brood. When mounds were shaded, S. invicta brood was evenly distributed directly under the surface of the mound rather than aggregating towards a specific side. The fire ant mound is important for thermoregulation because, compared to moundless subterranean nests, it absorbs heat more rapidly both in direct sunlight and shady conditions. Temperature tracking within the nest is key to understanding thermoregulatory placement of fire ant brood, as well as insight into the production of sexual brood and reproduction. Received 9 August 2007; revised 31 January 2008; accepted 7 February 2008.     

Interactive effects of soil-dwelling ants, ant mounds and simulated grazing on local plant community composition

Interactions between aboveground vertebrate herbivores and subterranean yellow meadow ants (Lasius flavus) can drive plant community patterns in grassland ecosystems. Here, we study the relative importance of the presence of ants (L. flavus) and ant mounds under different simulated grazing regimes for biomass production and species composition in plant communities. We set up a greenhouse experiment using intact soil cores with their associated vegetation.We found that plant biomass production in the short term was affected by an interaction between simulated grazing (clipping) and ant mound presence. Clipping homogenized production on and off mounds, while in unclipped situations production was higher off than on mounds. During the experiment, these differences in unclipped situations disappeared, because production on unclipped mounds increased. Plant species richness was on average higher in clipped treatments and patterns did not change significantly over the experimental period. Plant community composition was mainly affected by clipping, which increased the cover of grazing-tolerant plant species. The actual presence of yellow meadow ants did not affect plant community composition and production.We conclude that the interaction between ant mounds and clipping determined plant community composition and biomass production, while the actual presence of ants themselves was not important. Moreover, clipping can overrule effects of ant mounds on biomass production. Only shortly after the cessation of clipping biomass production was affected by ant mound presence, suggesting that only under low intensity clipping ant mounds may become important determining plant production. Therefore, under low intensity grazing ant mounds may drive the formation of small-scale plant patches.     

Microsatellite genotyping of red imported fire ant (Hymenoptera: Formicidae) colonies reveals that most colonies persist in plowed pastures

Our study focused on colony dynamics of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), in relation to the standard practice of planting rye grass (i.e., plowing) in the fall in Louisiana. Microsatellite molecular markers were used to determine genotypes of individuals from red imported fire ant colonies. These markers allowed us to monitor treatment effect by detecting changes in number and location of colonies in response to disking of pasture plots. Previous research on mound disturbance as a form of cultural control in pastures has produced mixed results. We found that the majority of colonies persisted on plots after plowing. Mound density and mound area, 5 mo after plowing, were not significantly different among treatments. In contrast, April measurements of mound volume were significantly smaller on plowed plots compared with control plots. A closer look at the rebuilding of mounds on plowed plots, during the 5 mo, showed that mound heights stayed below pretreatment measurements and they were significantly smaller than those of undisturbed mounds. Whether plowing has potential for use as a cultural control technique in reducing the impact of red imported fire ant mounds on agricultural practices in pastures remains to be seen. Conceivably, the best application of this technique will be in combination with other control measures in an integrated pest management approach to control red imported fire ants in pastures.     

Distribution of ant species and mounds (Formica) in different-aged managed spruce stands in eastern Finland

Mound‐building ants (Formica spp.), as key species, have large impacts on organisms and ecosystem functions in boreal Eurasian forests. The density, sizes and locations of ant mounds determine the magnitude and the spatial distribution of ant activities in forest ecosystems. Clear‐cutting can destroy wood ant colonies, and the species, abundance, dimensions and locations of ant mounds may change as forest stand structure changes with stand age. We compared ant species composition, ant mound numbers and dimensions, and the spatial distribution of mounds in Norway spruce [Picea abies (L.) Karst.] stands of different age (5, 30, 60 and 100 years) in eastern Finland. The mound density of Formica aquilonia Yarr. was greater in the two oldest stand age classes, while most mounds of Formica rufa L., Formica polyctena Först., Formica lugubris Zett., Formica exsecta Nyl. and Formica pressilabris Nyl. were found in the two youngest age classes. The mean volume, the volume per area and height/diameter ratio of F. aquilonia mounds increased with stand age. In the oldest stand age class, mounds were slightly smaller in well‐lit locations than in shade and near stand edges than further from the edges indicating that new mounds are established in well‐lit locations. Similarly, the longest slopes of the mounds faced south, indicating the importance of exposure to the sun. F. aquilonia mounds were concentrated near stand edges, and the spatial distribution of the mounds was aggregated in some stands. At the ecosystem level, the aggregation of ant mounds near stand edges may increase the edge productivity, as mounds concentrate resources to the edges and release nutrients after abandonment.     

Thermoregulatory trade-offs result from vegetation removal by a harvester ant

Abstract.  1. Analyses of ecological trade-offs help to explain how organisms balance competing demands. Harvester ants ( Pogonomyrmex occidentalis ), are conspicuous residents of shortgrass prairie in western North America; worker P. occidentalis actively clear all vegetation from the immediate vicinity of their large gravel mounds. This study is based on the prediction that vegetation clearing yields a thermal trade-off by increasing soil temperatures; during cool periods the resulting increase in soil temperature opens new time windows for activity, while during hot periods the soil temperature is more likely to exceed the maximum thermal tolerance for this species. To test the hypothesis that daily and seasonal trade-offs in ant activity result from vegetation removal, the effects of experimentally applied shade on activity patterns were measured.
2. Harvester ant activity correlated highly with ground temperature; experimental shading of ant mounds shifted daily activity patterns by lowering ground temperature. Shading in the morning significantly delayed the onset of ant activity by preventing solar warming of the mound. In contrast, mid-day experimental shading prevented elevation of ground temperatures to above 50 °C and allowed ants to remain active when lethally high temperatures would normally force them inside the mound.
3. A model derived from field data predicted surface ground temperature (and therefore ant activity) based on air temperature and solar radiation, under conditions of sun and shade. For each of six seasons modelled, shade removal yielded a net gain of activity time. These results indicate that vegetation removal by harvester ants produces an advantageous thermoregulatory effect by helping to maximise activity time.     

The harvester ant (Pogonomyrmex badius) midden: refuse or boundary?

Abstract. 1. P.badius Latreille, a harvester ant of the southern U.S.A., surrounds its nest mound with small bits of charcoal, previously believed to be incidental refuse, along with other components of the colony's midden.
2. Charcoal middens were removed from the nest mounds of colonies in northern Florida. These colonies collected new charcoal and replaced the middens within 7 days.
3. Activity rhythms, use of space, and interspecific aggression were compared in experimental and control colonies. When middens were removed, the frequency of invasions of the nest mounds by other species of ants increased. Foreign ants circled the nest mound and interfered with colony activities. Increased numbers of invading ants led to an increase in patrolling and defensive behaviour by the P.badius colonies.
4. The charcoal midden is not merely refuse. Instead, it acts as a boundary that deters ants of other species from coming onto the P.badizls nest mound. Ants may use charcoal bits as a repository of a chemical substance functioning as a territorial marker.     

Impact of Formica exsecta Nyl. on seed bank and vegetation patterns in a subalpine grassland ecosystem

The mound building ant Formica exsecta Nyl. is widely distributed in grassland ecosystems of the Central European Alps. We studied the impact of these ants on seed bank and vegetation patterns in a 11 ha subalpine grassland, where we counted over 700 active ant mounds. The mounds showed a distinct spatial distribution with most of them being located in tall‐grass, which was rarely visited by ungulates (red deer; Cervus elaphus L.). Heavily grazed short‐grass, in contrast, seemed to be completely avoided by ants as only few mounds were found in this vegetation type. The species composition of the ant mound and grassland seed banks was quite similar, i.e. from 15 common plant species 12 were found in both seed bank types. We found the same proportions of myrmecochorous seeds in ant mound and grassland soil samples. In contrast, the number of seeds was 15 times higher in mound compared with the grassland soil samples. Also, the vegetation growing on ant mounds significantly differed from the vegetation outside the mounds: graminoids dominated on ant mounds, herbaceous and myrmecochorous species in the grassland vegetation. We found significant continuous changes in vegetation composition on gradients from the ant mound centre to 1 m away from the mound edge. Overall, F. exsecta was found to have a considerable impact on seed bank and vegetation patterns in the grassland ecosystem studied. These insects not only altered grassland characteristics in the close surrounding of their mounds, but also seem to affect the entire ecosystem including, for example, the spatial use of the grassland by red deer.     

Efficacy of broadcast and perimeter applications of S-methoprene bait on the red imported fire ant in grazed pastures

The red imported fire ant, Solenopsis invicta (Buren), is a major pest in the United States because of its painful sting. Toxic bait has been an important management tool against fire ants, but site registrations prohibit applications of most baits on grazed pastures. Extinguish, containing the insect growth regulator methoprene, was selected for this study because it has a broad site registration that includes grazed pastures. The primary objective of this research was to evaluate the efficacy for control of red imported fire ants by using broadcast applications of methoprene bait at a label rate of 1,121 g/ha versus applications around the perimeter of a target area at the reduced rate of 280 g/ha. Grazed pastures in Lee County, Alabama, and Chambers County, Alabama, were selected for this study, with broadcast treatments, perimeter treatments, and controls replicated three times at each site. All mounds were counted and rated using the USDA population index before applications and then at 8 and 16 wk posttreatment. Perimeter applications did not significantly reduce S. invicta mound abundance, but bait treatments significantly reduced mound abundance at 16 wk posttreatment at site 1 where applications were conducted in early evening. However, broadcast applications were not effective at site 2 where treatments were conducted in early morning with warmer temperatures. Emergence of winged alates was observed at 12 wk posttreatment, followed by a high density of incipient mounds that may have masked the full treatment effect of methoprene applications at site 2. Methoprene bait was effective in reducing abundance of S. invicta only when full label rates were applied.