Isolation, identification and potential uses of sex pheromones for three pests of cotton in Australia

The Australian cotton industry is heavily dependent on chemical insecticides for pest control. As a result, a number of environmental issues involving off-farm movement of these pesticides have been raised for the industry. One of the key issues in meeting the challenges of growing cotton in tomorrow's world involves pest management in a more environmentally friendly way. This involves reduction of pesticide use and adoption of integrated pest management (IPM) approaches. Introduction of transgenic cotton in recent years and application of insecticides targeting individual species has enabled a drastic reduction in pesticide use. This allows the numbers of important beneficial insects to build up, aiding in pest control. On the other hand, species like the green mirid (Creontiades dilutus), cotton tipworm (Crocidosema plebejana) and rough bollworm (Earias huegeliana), which were not major problems under intensive use of insecticides are forecast to be more significant pests, which will require a re-evaluation of IPM in cotton. One potential component of IPM involves the use of insect sex pheromones in mating disruption, monitoring, attract-and-kill and mass trapping. Pheromones could be used to predict oviposition on a field by field basis and also give useful indications of the overall abundance of the pests mentioned above. Identified pheromones therefore could be used in area-wide pest management schemes. Pheromones can also be used in attract-and-kill strategies or for mating disruption. Although the Australian cotton industry has not previously made significant use of these techniques, there are ecological reasons for believing that they may be more applicable to some emerging pests than to the key pests of cotton under previous pest management regimes, Helicoverpa spp. This project was carried out to identify the sex pheromones of three pests of cotton in Australia - the rough bollworm, cotton tipworm and green mirids, to test attractive blends and to investigate potential uses of their sex pheromones as part of the general IPM system of the Australian cotton industry

Sex pheromones of the green mirid, Creontiades dilutus

The green mirid, 'Creontiades dilutus' (Stål) (Hemiptera: Miridae) is one of the key species in the "sucking pests complex" in cotton and other field crops such as sunflower, pulses and lucerne in Australia. It is now becoming a significant pest with the reduction of broadspectrum insecticides and the use of more selective chemicals in transgenic cotton. Semiochemicals like sex pheromones might be useful in managing this pest as monitoring tools, in mating disruption or in an attract-and-kill system

Potential for pheromone-based attract and kill and mating disruption of the green mirid 'Creontiades dilutus' (Stål) (Hemiptera: Miridae).

Attempts were made at applying green mirid pheromones in a sprayable formulation for mating disruption and attract-and-kill in 'Creontiades dilutus' (Stål), an emerging significant pest of cotton and other crops in Australia. In the mating disruption trials, a total trap shutdown for 2 days was observed. The short trap shutdown period is thought to have arisen from the formulation used. In the attract-and-kill work, efforts made to locate and count dead mirids for quantification did not work. Either the insecticide did not kill the mirids fast enough, resulting in their moving away from the treated row before dying, or the low numbers of mirids present made the sampling method ineffective. However, the trap results suggest that attract-and-kill for male green mirids remains a promising option. As with mating disruption, however, further work needs to be done on a long lasting formulation to overcome potential problems with reinvasion of treated fields

Sex Pheromones of the Green Mirid, 'Creontiades dilutus' (Stål) (Hemiptera: Miridae)

Whole body extracts and air collections from 'Creontiades dilutus' males and females were analyzed to identify the sex pheromone components. The major component, hexyl hexanoate was found in whole body extracts and air collections from both sexes, while the min or component, (E) -2-hexenyl hexanoate, was only present in the female air collections. Field trapping experiments were conducted to determine the attractiveness of either of the single components and various binary blends to males. The optimum blend that consistently caught males in pheromone traps was a 5:1 ratio of hexyl hexanoate and (E) -2-hexenyl hexanoate. Trapping studies also showed that green mirids came to pheromone traps only between 18:00 and 06:00 h, suggesting that they might be nocturnal rather than diurnal insects as previously thought

Potassium Application Positively Modulates Physiological Responses of Cocoa Seedlings to Drought Stress

With increasing frequency and intensity of dry spells in the cocoa production zones of West Africa, strategies for mitigating impact of water stress on cocoa seedling survival are urgently required. We investigated the effects of applied potassium on biomass accumulation, physiological processes and survival of cocoa varieties subjected to water stress in pot experiments in a gauzehouse facility. Four levels of potassium (0, 1, 2, or 3 g/plant as muriate of potash) were used. Soil water stress reduced plant biomass accumulation (shoot and roots), relative water content (RWC), chlorophyll content and fluorescence. Leaf phenol and proline contents were increased under water stress. Additionally, compared to the well-watered conditions, soils under water stress treatments had higher contents of exchangeable potassium and available phosphorus at the end of the experimental period. Potassium applied under well-watered conditions reduced leaf chlorophyll content and fluorescence and increased leaf electrolyte leakage, but improved the growth and integrity of physiological functions under soil water stress. Potassium addition increased biomass partitioning to roots, improved RWC and leaf membrane stability, and significantly improved cocoa seedling survival under water stress. Under water stress, the variety with the highest seedling mortality accumulated the highest contents of phenol and proline. A significant effect of variety on plant physiological functions was observed. Generally, varieties with PA 7 parentage had higher biomass partitioning to roots and better seedling survival under soil moisture stress. Proportion of biomass partitioned to roots, RWC, chlorophyll fluorescence and leaf electrolyte leakage appear to be the most reliable indicators of cocoa seedling tolerance to drought

Stem borer-attributed mortality of shea trees in Northern Ghana: Infestation, tree death and associated factors

The shea tree is important in several African countries, supporting livelihoods and providing foreign exchange. Shea tree mortality as a result of pest infestation was reported in two parklands in Northern Ghana in June 2018. This study reports on tree mortality in the parklands with reference to stem borer infestation and related characteristics. Standing shea trees in the parklands were randomly sampled to determine stem borer infestation and its role in tree mortality. Nutrient concentration of soil and pest-infested shea were also analyzed. Stem borer infestation at Maluwe (34%) was higher than Gindabo (2%) with tree mortality of 4% and 0%, respectively. Stem borer (Philematium festivum) larvae were absent on standing shea trees but pervasive on windthrown trees. Nutrient (N, P, K, Mg) concentration was significantly different among plant parts, pest infestation status of tree and their interaction at Maluwe. However, at Gindabo, there was no significant difference in pest infestation status and plant parts-pest infestation status interaction for N and plant parts for K. At Maluwe, stem borer-infested trees had the highest N and K levels, while co-infested and un-infested trees had the highest P and Mg levels, respectively. However, un-infested trees contained the highest nutrient levels at Gindabo. Soil characteristics of both sites were similar and although soil nutrient levels at Gindabo were relatively higher, the shea trees had lower nutrient accumulative potential. The reported death was due to abiotic factors including wind/storms that predisposed the trees to proximate factors such as stem borers

Effect of Cocoa Beverage and Dark Chocolate Consumption on Blood Pressure in Those with Normal and Elevated Blood Pressure: A Systematic Review and Meta-Analysis

Cocoa is a major dietary source of polyphenols, including flavanols, which have been associated with reduced blood pressure (BP). While earlier systematic reviews and meta-analyses have shown significant effects of cocoa consumption on systolic BP, limitations include small sample sizes and study heterogeneity. Questions regarding food matrix and dose of polyphenols, flavanols, or epicatechins remain. This systematic review and meta-analysis aimed to investigate the effects of ≥2 weeks of cocoa consumption as a beverage or dark chocolate in those with normal or elevated (p < 0.05, all). Compared with cocoa, chocolate lowered the weighted mean of resting systolic BP (−3.94 mmHg, 95% CI [−5.71, −2.18]) more than cocoa beverage (−1.54 mmHg, 95% CI [−3.08, 0.01]). When the daily dose of flavanols was ≥900 mg or of epicatechin ≥100 mg, the effect was greater. Future, adequately powered studies are required to determine the optimal dose for a clinically significant effect