Survey and Assessment of the Natural Enemies of Water Hyacinth,Eichhornia crassipes

Abstract

In northern Queensland, the addition of 2,4,5‐T butyl ester was found to be unnecessary to maintain the control of Echinochloa colona (L.) Link and Cyperus Iria L. In dry seeded rice when propanil rates were reduced below the registered rate of 4 kg a.i. ha^?1. Adequate weed control was obtained with 1.3 kg a.i. ha^?1 propanil alone. No adverse effects on rice yield were found with any of the propanil × 2,4,5‐T treatments. Low rates of propanil, 1.3 and 0.72 kg a.i. ha^?1, compared favourably with pre‐emergence treatments of thiobencarb, butachlor, oxyfluorfen and pretilachlor (plus a safener) when weed yields were low. Where water management was poor and Ischaemum rugosum Salisb. was the dominant weed, oxyfluorfen applied pre‐emergence at 0.96 kg a.i. ha^?1 produced a higher rice and a lower weed yield than the low rates of propanil. In three of the five experiments, weed growth was insufficient to depress rice yields significantly.     

Transfer of indoxacarb among workers of Coptotermes formosanus (Isoptera: Rhinotermitidae): effects of dose, donor:recipient ratio and post-exposure time

Horizontal transfer of indoxacarb among workers of the Formosan subterranean termite, Coptotermes formosanus Shiraki, was examined under laboratory conditions. The effects of dose (0, 10, 20, 50, 100 or 200 ng AI per donor), donor:recipient ratio (1:1, 1:4 or 1:9) and post-exposure time (2, 4, 8, 16, 20 and 24 days) on lethal transfer of indoxacarb were investigated using a donor/recipient model in groups of 100 workers. Transfer of lethal doses from donors to recipients was evidenced by significant recipient mortality in 13 out of 15 treatments within 24 days post-exposure. Dosage significantly affected indoxacarb transfer. Higher doses resulted in greater recipient mortality than lower doses. The highest dose tested resulted in 100% death of recipients and donors within 20 days. A dose of 100 ng resulted in recipient mortalities ranging from 68 to 100%, whereas doses < or =50 ng killed <60% of recipients within 24 days. Donor:recipient ratio also had considerable effect on indoxacarb transfer. At 24 days post-exposure, greater recipient mortalities were observed at ratios > or =1:4 at doses > or =20 ng, but only at a ratio 1:1 at dose 10 ng. Recipient mortality increased significantly as post-exposure time increased. The higher the doses applied on donors, the shorter were the times required for the onset of recipient mortality to occur and for recipients to reach maximum mortality. Significantly greater recipient mortalities were not observed at doses 20 and 50 ng until more than 20 days post-exposure, indicating a delayed activity of indoxacarb. Possible transfer mechanisms are discussed.     

Notices

Abstract

Seed‐bed types, fertilizers, cassava stem portions, planting time and yam cultivars were studied for the incidence of termites in cassava and yam fields. Planting cassava on ridges reduced the incidence of termites and significantly (P<0.05) increased tuber yield. The bottom stem portion of cassava stick was the least attacked by termites. Planting cuttings when rains became steady reduced termite incidence. NPKMg (12:12:17:2) suppressed termites in yam and improved yield significantly. Delay in harvesting yam tubers increased termite infestation. Yield loss was highest for Dioscorea rotundata cv. Nwopoko, with losses of more than 5 metric tonnes/ha when harvest was done after December in termite infested soil. Chinese yam showed the greatest resistance to termites.     

Distribution of a juvenogen and its metabolites in a laboratory system during juvenogen-induced caste differentiation in a termite, Reticulitermes santonensis (Isoptera: Rhinotermitidae)

BACKGROUND: Juvenoids and juvenogens have been for many years considered promising candidates for control of pest insect species including termites. Their use as termite pest management agents requires the generation of knowledge concerning their degradation and distribution in time and space. Groups of 40 Reticulitermes santonensis de Feytaud workers were provided with wood impregnated with a juvenogen, ethyl cis-N-{2-[4-(2-butyryloxycyclohexylmethyl)phenoxy]ethyl}carbamate, labelled with tritium in the benzene ring (305 GBq mmol(-1)). After 14 days the radioactivity was determined in all elements of the experimental system. RESULTS: The majority of the input activity was detected in the wood, only about 1% in the bodies of surviving termites and 1% in the substrate. A considerable part of the input activity was probably lost as gaseous termite metabolites. The activity in workers was significantly higher than in presoldiers, which had differentiated under the influence of the labelled juvenogen. A stable value of radioactivity was detected on the body surfaces. CONCLUSIONS: The results suggest good stability of the compound in the wooden carrier and low contamination of the environment with non-gaseous residuals, together with the desired biological impact on termite caste differentiation.     

Targeted elimination of the exotic termite,Nasutitermes corniger (Isoptera: Termitidae: Nasutitermitinae), from infested tracts in southeastern Florida

Populations of the arboreal termite, Nasutitermes corniger, discovered in Dania Beach, Florida in 2001 were surveyed and treated for eradication, beginning in 2003. Most N. corniger nest locations were cryptic and some nests contained over 1 million termites. Field efficacy of fipronil (Termidor® SC) and imidacloprid (Premise® 2) were compared in initial treatments, and fipronil was selected for termite-active sites through 2010. In 2006, expanded survey work was discontinued. By 2010 all sites within the original survey area were termite-free. In 2011, a new population of N. corniger was discovered beyond the original 2003 infested tracts. A new (2011–2012) survey revealed a total of four areas outside the original tracts that were infested with N. corniger. No tract treated with fipronil between 2003 and 2010 showed evidence of renewed termite activity in 2011–2012. New application procedures using nest-only and fipronil dust treatments were instituted in May 2012. Live termites were still found within the 2011–2012 treatment area as of November 2013. Very slow but continued spread of N. corniger in tropical urban Florida will have economic consequences as a result of nuisance and structural damage.     

陕西、甘肃园林树木白蚁种类及为害情况

在陕西、甘肃白蚁分布区,对园林树木的白蚁种类及其为害情况进行了调查.结果显示,陕西、甘肃地区为害园林树木的白蚁种类共有3科5属12种,其中主要危害蚁种为尖唇散白蚁、黄胸散白蚁和圆唇散白蚁,次危害蚁种为陕西树白蚁和陇南树白蚁.陕西、甘肃受白蚁为害的树木共20种.3种主要危害蚁种为害的主要树种为杨树、刺槐、国槐、银杏、李树、柳树和构树.另外,柳树、杨树和刺槐也易遭陕西树白蚁和陇南树白蚁侵害.园林树木蚁害整体上不是很重,但局部区域或景点有些单一树种受害率达10％以上,有些甚至达到20％以上,受害率已与长江以南地区很接近,应引起相关部门的重视.     

杭州植物园白蚁为害现状及防治对策

白蚁是杭州重要的园林害虫,近年来为害猖獗,严重影响了植物的生长,破坏了生态景观。调查表明,为害杭州植物园的白蚁主要有4种,其中又以黑翅土白蚁为害最为严重。白蚁防治应遵循“预防为主,防治结合”的原则,采取综合防治。杭州植物园的白蚁防治应根据其自身条件,在加强园林养护的基础上,宜采取药剂驱避、喷粉灭杀、诱杀包诱杀相结合的防治措施。     

Mobility,longevity and activity of chlorfenapyr in soils treated at a termiticidal rate

BACKGROUND: The mobility, longevity and termiticidal activity of chlorfenapyr applied to soils at the termiticidal labeled rate was evaluated for 30 months after treatment (MAT) in a greenhouse study. RESULTS: There was little dissipation of chlorfenapyr in soil treated at the labeled rate for perimeter treatments for the prevention and control of termite infestations. Chlorfenapyr was detected in soil immediately below the initially treated soil in the packed soil columns. This was likely due to settling of soil. The treated soil remained toxic to subterranean termites in 3 and 7 day bioassays over the duration of the study. The treated soil displayed slow‐acting properties regarding toxicity to termites. Trace amounts of chlorfenapyr were detected in the eluates of packed soil cones. CONCLUSION: The commercial formulation of chlorfenapyr used in this study (21.45% concentrate diluted to 0.125% prior to application) killed 100% of the tested subterranean termites for at least 30 months. Copyright © 2012 Society of Chemical Industry     

A review of subterranean termite control practices and prospects for integrated pest management programmes

Soil insecticide barriers have been the single most important tool for subterranean termite control in the last half century, but limitations with current soil termiticides have provided the impetus to look for alternatives in recent years. One such alternative is the monitoring--baiting programme. Monitoring stations to detect termites are placed in the soil surrounding a structure. Once termites are found in the stations, monitoring devices are replaced with slow-acting baits such as the chitin synthesis inhibitor, hexaflumuron. Field studies have indicated that termite colonies were eliminated using less than 1 g of hexaflumuron. After the elimination, monitoring resumes and bait is applied if new termite activity is detected. The monitoring and baiting procedure form the basis for an ongoing programme to protect structures from subterranean termite infestation. Although the cost--benefit model developed for agricultural integrated pest management cannot be applied directly to termite control, the underlying concept for using a cost-effective approach remains the same. The benefits of the monitoring--baiting programme over conventional soil treatment are a reduction in pesticide applied per unit and the elimination of termite populations near structures, resulting in the reduction of liability and damage potential. It is expected that the data management system when used in conjunction with the monitoring--baiting programme will provide a database to improve its cost-effectiveness continuously.     

海宁城市园林绿化白蚁危害情况调查和防治

对海宁市城市园林绿化白蚁危害情况进行抽样调查,发现危害城市园林的白蚁有2科3种,危害优势种为黑翅土白蚁。香樟为易受害树种,城市园林总体蚁害率为40.01%。针对不同园林特点,应选择合适的防治方法,可以达到有效防治白蚁危害的目的。     

Efficacy of hexaflumuron against the fungus-growing termite Pseudacanthotermes spiniger (Sjöstedt) (isoptera,macrotermitinae)

The efficacy of hexaflumuron, a benzophenylurea insecticide, has been studied for the first time on a fungus-growing termite (Pseudacanthotermes spiniger Sjöstedt, Macrotermitinae). Results show that hexaflumuron could be useful in treating infestations of such pest species, which are of great economic importance in many tropical and equatorial countries. Foraging workers harvested and introduced treated food into the nest and subsequently contaminated the brood by trophallaxis. Hexaflumuron showed potent larvicidal activity. The compound did not appear to be rapidly degraded by the digestive enzymes of termite workers, nor by the symbiotic fungus Termitomyces eurhizus Heim growing on fungus combs. This chitin synthesis inhibitor did not act as a fungicide, since growth of the mycelium of this fungus was not inhibited in vitro. © 1998 Society of Chemical Industry     

滕王阁白蚁的综合治理

介绍了滕王阁白蚁种类、危害情况、原因及对滕王阁蚁害采取传统、诱杀、监控、装修预防等防治处理方法,有效地控制了白蚁的蔓延危害,并对类似历史建筑白蚁检查防治提出了综治措施和建议。     

Nutrients affecting food choice by the pest subterranean termite Coptotermes gestroi (Isoptera: Rhinotermitidae)

Coptotermes gestroi is a subterranean termite from Asia, introduced accidentally to Brazil, where it is responsible for substantial damage in urban areas. The foraging range of this species frequently overlap with that of Heterotermes tenuis, a native termite also considered to be a severe pest. The greatest challenge in controlling these termites is to develop baits suitable for both species. A critical issue is to select compounds that act as common phagostimulants. We examined whether the feeding preferences of C. gestroi for some nutrients were similar to those already reported for H. tenuis. A double choice design was used. Consumption was evaluated by change in the dry mass of paper discs after termite feeding. C. gestroi fed preferentially on discs treated with a solution of sucrose + yeast. However, insects did not choose urea at 0.015 g/ml, one of the preferred solutions for H. tenuis. These results indicate that the two termites have different feeding preferences, and we suggest future use of sucrose + yeast in baits for management of C. gestroi.     

毒死蜱、联苯菊酯在模拟房屋白蚁预防施工的 野外试验地的残留动态研究

研究了在野外条件下不同施药量和不同处理方法毒死蜱和联苯菊酯在土壤中的降解动态。结果表明,联苯菊酯的持效期比毒死蜱的长。 在白蚁防治推荐使用浓度下,两种农药在有覆盖处理组的降解都比无覆盖处理组的慢。 同时,施药量对降解速率有重要影响。 毒死蜱在施药量30 g/m2、20 g/m2有覆盖处理组及30 g/m2无覆盖处理组的半衰期依次为186.3、171.3、60.2 d。在施药量为1.875 g/m2、1.250 g/m2有覆盖处理组及1.875 g/m2无覆盖处理组中,联苯菊酯的半衰期依次为302.6、203.3、107.0 d。     

Effects of non-repellent termiticides on the tunneling and walking ability of the eastern subterranean termite (Isoptera: Rhinotermitidae)

BACKGROUND: Non-repellent insecticides, including fipronil and indoxacarb, are becoming increasingly important for soil treatments to manage the eastern subterranean termite, Reticulitermes flavipes (Kollar). The effects of these insecticides on termite walking and tunneling behavior could significantly reduce their efficacy against colonies. RESULTS: Groups of R. flavipes were exposed to several concentrations of commercial formulations of fipronil and indoxacarb, and the ability of treated termites to tunnel in soil and walk was assessed. Increasing insecticide concentration resulted in a reduction in the ability of R. flavipes to walk, tunnel and form tunnel branches; the importance of these effects on the use of non-repellent insecticides is discussed. CONCLUSION: Exposure of R. flavipes to 1, 10 or 50 mg L⁻¹ of fipronil or 50, 100 or 200 mg L⁻¹ of indoxacarb significantly reduced termite walking and tunneling and the number of tunnel branches. Distance walked (ca 73 mm) by untreated control termites did not change over time for at least 16 h after treatment; control termites formed ca 150 cm of tunnels with ca 40 branches. Copyright © 2012 Society of Chemical Industry     

Immobilisation of bifenthrin for termite control

BACKGROUND: Termites are worldwide pests causing considerable damage to agriculture, forestry and buildings. While various approaches have been tried to eliminate termite populations, the relevant toxicants are associated with certain risks to the environment and human health. RESULTS: In this study, to combine the merits of effective chemical control by bifenthrin and a drug photoimmobilisation technique, silk fibroin was used as a carrier to embed bifenthrin, which was then photoactively immobilised by ultraviolet treatment on the surface of wood (cellulose). The immobilised bifenthrin embedded in the photoactive silk fibroin was characterised by Fourier transform infrared spectroscopy (FTIR), ultraviolet absorption spectroscopy (UV), fluorescence measurement and CHN analysis. The surface structures and biological activity were examined by scanning electron microscopy (SEM), atomic force microscopy (AFM), electron spectroscopy for chemical analysis (ESCA) and bioassays respectively. CONCLUSIONS: The results indicate that the embedded and immobilised bifenthrin has been very well protected from free release and has a long‐term stability allowing slow release with a high efficiency against termites at a low dose of 1.25 µg cm^?2. This study provides a novel and environmentally benign technique for termite control by photoimmobilising silk‐fibroin‐embedded bifenthrin on the surface of materials that are otherwise easily attacked by termites. Copyright © 2010 Society of Chemical Industry     

吡虫啉在土壤中的稳定性及其在白蚁防治中应用探讨

为了明确吡虫啉对白蚁的持效性,研究了室内与野外模拟施工条件下降解半衰期。室内研究发现,在壤土中,吡虫啉初设浓度分别为20、50mg／kg其降解半衰期分别为157．5、198．0d;在砂壤土中,吡虫啉初设浓度分别为20、50mg／kg其降解半衰期分别为187．3、433．1d。同一初设浓度下,吡虫啉在壤土中比在砂壤土中降解得快。在同一种质地土壤中,浓度高者其降解半衰期相应变长。在野外试验中,初设浓度分别为0．05％、0．1％、0．15％,在0～5cm层土壤中吡虫啉的降解半衰期分别为123．8、130．8和133．4d：在5～10cm层分别为216．6、210．0和216．6d。这与建筑物预防15年的要求差距相差甚远。建议实际施工中要注意跟踪补施。     

Comparative effects of vetiver oil,nootkatone and disodium octaborate tetrahydrate on Coptotermes formosanus and its symbiotic fauna

The potential of vetiver oil and nootkatone as wood treatments against Coptotermes formosanus Shiraki was examined by assessing the effects on termite tunneling, feeding activity and survival, and the consequences on the symbiont protozoa responsible for wood digestion. Comparisons were made with non-treated wood (control), wood treated with the borate compound Tim-Bor (a commonly used lumber preservative) and absence of a food source (starved termites), using choice and no-choice tests. All wood slices were prepared at the same time using a 10 g liter(-1) solution of each substance and were tested in four different sessions over one year to investigate longevity of the effects. Termites had to tunnel through sand to exploit the food sources, consisting of two wood slices, placed on opposite sides of the experimental enclosure. No-choice tests showed that in the presence of vetiver oil or nootkatone, tunneling activity was always the lowest; wood consumption, termite survival and flagellate numbers and species distribution were significantly different from the control and similar to the results obtained for starved termites and with Tim-Bor-treated wood. Nootkatone negatively affected termites for 12 months and was longer lasting than vetiver oil. In choice tests, when vetiver oil or nootkatone were present, termites exhibited a significant preference for non-treated wood. Our results confirmed both the toxicity and absence of repellency of Tim-Bor. Vetiver oil and especially nootkatone affected Formosan subterranean termites and their protozoa, acting as arrestants, repellents and feeding deterrents, and represent a promising natural alternative for the control of this invasive pest.