Farmers' Awareness and Use of IPM for Soybean Aphid Control: Survey Results for the 2004, 2005, and 2006 Crop Years

In response to the introduction and rapid spread of soybean aphid as a major new invasive pest of soybean in North America, farmers who attended winter crop meetings in four states in North Central US were surveyed about their treatment of and knowledge about soybean aphids for crop years 2004, 2005, and 2006. Thirteen percent, 84%, and 35% of the farmers indicated they had treated for soybean aphid in 2004, 2005, and 2006, respectively. The average of the soybean acreage treated in each year was 50%, 87%, and 81%, respectively. Overall, the farmers showed a good understanding of soybean aphids and their impact on soybeans. Over 80% knew soybean aphids could repopulate and cause yield damage after an insecticide treatment. Seventy-five percent knew aphids damaged soybeans by sucking sap. Almost 80% said the frequency with which aphids should be treated for profitable control depends on aphid counts, weather conditions, and plant stage. On average, just under 70% considered an average of 250 aphids per plant to be the lowest density for profitable insecticide spraying. Scouting reports were selected by 84 to 94% of the farmers as very important information for the treatment decision; plant growth stage was the second most frequent selection.Crop Production/Industries,

Farmers’ Awareness and Use of IPM for Soybean Aphid Control: Report of Survey Results for the 2004, 2005, 2006, and 2007 Crop Years

In response to the introduction and rapid spread of soybean aphid, farmers in the Upper Midwest were surveyed about their treatment of and knowledge about soybean aphids for crop years 2004, 2005, 2006, and 2007. Overall, the farmers showed a fairly good understanding of soybean aphids and their impact on soybeans. Over 80% said soybean aphids could be treated and repopulate in the same crop year. For 2004-2006, at least 75% of the farmers said aphids damaged their soybeans by sucking sap. However this percentage dropped to 59% for 2007 with a greater percentage pointing at a combination of damage methods. This lower percentage for 2007 may be due to a broader, randomly selected sample of farmers who received the surveys by mail versus farmers who attended meetings in the first three years. However, even though fewer seemed to have a clear understanding of how aphids damage soybeans, other measures indicate a stable or improved understanding of soybean aphid biology and control. Over 70% said the frequency with which aphids should be treated for profitable control depends on aphid counts, weather conditions and plant growth stage. About a third of the farmers believed that aphids inflict the most damage during early flowering through pod set (R1-R3); however, about a third also thought aphids could inflict the most damage at any stage. Over half the farmers considered the lowest aphid density for profitable aphid control to be 250 aphids per plant. Over 80% said scouting reports were very important for making a decision to treat for aphids; over half the farmers said plant growth stage was also very important.Crop Production/Industries,

Dynamics of structural transformation: An empirical characterization in the case of China, Malaysia, and Ghana

"The paper develops a metric of structural transformation that can account for the production of new varieties of goods embodying advancements in technological know-how and design. Our measure captures the dynamics of an economy's transformation and can be viewed as an extension of Hausmann and Klinger's static measure. We apply our measure to four-digit-level SITC trade data of China, Malaysia, and Ghana over the period 1962–2000. The results show that two important factors characterize the rapid transformation of the Chinese economy: the high proximity of its export basket to three main industrial clusters—capital goods, consumer durable goods, and intermediate inputs—and the increase in the values of the new goods belonging to those three clusters. Malaysia exhibits a similar but more modest pattern. In contrast, the structure of the Ghanaian economy appears unchanged over the entire 1962–2000 period. That economy is dominated by primary goods clusters, and the values of the goods in those clusters have remained relatively low. We also discuss qualitatively the role of policies and institutions in spurring transformation in the three countries." from authors' abstractStructural transformation, Discovery, technological change, Development strategies,

Producers' Use of Crop Borders for Management of Potato Virus Y (PVY) in Seed Potatoes

Potato virus Y (PVY) is a very serious problem throughout most major seed potato producing states. Seed potato producers in Minnesota and North Dakota were surveyed in early 2005 to assess their perception of the profitability and risks associated with using crop borders to manage PVY in seed lots. Five of the 23 producers responding (a 25% response rate) said they had used crop borders in 2004. These 23 producers entered 152 seed lots into state seed certification programs. On average, producers had less than 0.1 seed lots rejected for PVY based on summer inspection. The average number of seed lots rejected in winter trials was 1.7. Of the 152 seed lots, these producers said they had entered into state seed certification programs, they reported detailed information on 108 lots. Generations 1 and 2 were the most likely generations to be protected by a crop border. Of these 108 seed lots, 104 passed summer inspection for PVY. Seventy-four percent of the 89 lots sent in for the winter test were reported to have passed. The use of crop borders was significant in explaining whether a seed lot had passed the winter test or not. Thirty-one (97%) of the 32 seed lots that were planted within a crop border passed the winter test while 31 (54%) of the 57 seed lots that were not planted with a crop border passed the winter test. No relationship was found between the choice of border crop and passing the winter test. Producers also were asked to state their agreement or disagreement with several statements regarding their knowledge and opinions on use of crop borders.Crop Production/Industries,

ECONOMIC ANALYSIS OF USING A BORDER TREATMENT FOR REDUCING ORGANOPHOSPHATE USE IN SEED POTATO PRODUCTION

Recent research shows initial colonization of potato fields by winged green peach aphid is concentrated at field edges. This suggests that insecticides applied only to field margins during initial colonization would largely eliminate a colonizing aphid population, conserve natural enemies in the field center, and reduce insecticide use. To better understand the costs and benefits of reducing organophosphate use, the six participating growers were interviewed to ascertain their reason for participating and their satisfaction with the border only treatment method as well as their estimated net economic benefits. Five of the farms ranked cost reduction as the most important reason for participating. The sixth farm ranked reducing virus spread as the most important reason with cost reduction as their second most important reason. The average cost savings over all 28 participating fields of using the border treatment is estimated to be $23.85 per acre for the entire field-a 93% savings. Almost all the farmers found the border treatment method to be successful at aphid control. None of the farmers observed any impact on the physical yield of seed potato. All the fields were certified during the summer except for one of Farmer F's fields that was lost because of off type. In conclusion, the border treatment method seems likely to be adopted by many farmers since the potential cost saving is large and farmers dislike Monitor. However, some farmers may resist the method due to scouting requirements and costs. Also, farmers with fields that do not meet the uniformity requirements of the border treatment will not be successful in their use of the border method.Crop Production/Industries,

Analyzing Growth and Welfare Effects of Public Policies in Models of Endogenous Growth with Human Capital: Evidence from South Africa

Since the abolition of its Apartheid regime in 1994, South Africa has launched a massive program of education, which has been financed through resources representing on average 21% of the national budget or 7% of GDP. Today, the GDP share of public spending on education is 1.3 times the average of industrialized countries (5.4%) and almost twice that of developing countries (3.9%). In this paper, we simulate fiscal policy experiments to analyze the growth and welfare effects of a shift in the allocation of government expenditures between public spending on education and transfers as well as those of a change in the tax rate in a model of endogenous growth with human capital accumulation for the South African economy. The results of simulations demonstrate that a shift in the allocation of fiscal resources between educational spending and transfers does not affect the long run allocation decisions. In the transition, however, this shift generates a negative effect on the rate of growth of GDP. In fact, a reallocation of expenditures shifts resources away from saving and toward consumption, and translate into lower rate of growth but higher welfare. Nonetheless, these growth and welfare effects are very small. On the other hand, a tax cut generates growth effects in the long run as well as in transition. In fact, reducing or cutting the tax rate in the long run lowers the interest rate, which in turn creates disincentives for saving and results in low rate of growth of GDP. However, in the transition, it reduces or removes distortions and translates into high work effort, high accumulation of human capital, and thus high rate of growth of GDP. Nonetheless, its welfare effect is negative

A Bioeconomic Model of the Soybean Aphid Treatment Decision in Soybeans

Since its first detection in the North Central region in July 2000, the soybean aphid (Aphis glycines Matsamura) has caused considerable loss in soybean (Glycine max L.) yield, bean quality, and producer income. Discovered first in Wisconsin and then in adjoining states, it is currently distributed in 21 US states and parts of Canada. In 2003, over 42 million acres of soybean in the North Central US were infested and over 7 million acres were treated with insecticides to control soybean aphid (Landis et al. 2003). Populations exceeding 24,000 aphids per plant and 40% losses in seed yield have been reported (DiFonzo & Hines 2002). Even prior to the outbreak of 2003, the Soybean Strategic Pest Management Plan identified soybean aphid as one of the key drivers of insecticide use in the North Central region (Smith & Pike 2002). This paper first describes the interaction with and impacts of the soybean aphid on soybean. Then the treatment decision model is developed and impacts analyzed. In the last section, some comments are made on how the results of this work on soybean aphids can be adapted to the impact of soybean rust (Phakopsora pachyrhizihas), another new pest of soybean. The following paragraphs summarize these parts in more detail. Unlike other corn-soybean insect pests, the soybean aphid treatment decision is more complex than growers are used to making. The presence of pests such as weeds, diseases, nematodes, and other more common pests is usually known before planting decisions are made. These pests also are slower to reproduce and more predictable in their growth rate than soybean aphid. Thus treatment and timing decisions to control them are made within a more stable situation. With soybean aphids, however, growers face a pest with unpredictable colonization and a long window of crop susceptibility. Also, soybean aphids are not like other pests in that their populations are capable of doubling every 2-3 days and can rebound after insecticide applications. The soybean aphid affects plant growth and reproduction directly. Soybean yield can be affected eventually at high populations. At the present time, entomologists are not certain about what defines a population high enough to impact yield. The impact of aphids depends on many factors, the most important being: initial date of aphid colonization, aphid population growth rates, length of colonization, soybean plant growth stage, treatment timing and efficacy, the lag between the decision to treat and application of insecticide, aphid population regrowth and recolonization, and weather. Soybean is more susceptible to aphids in the earlier reproductive stages of plant growth (R1-R5) compared to later stages. Aphid colonization is rare in earlier vegetative stages and may not occur until the most susceptible period is over. Currently available insecticides are highly effective, but with essentially no residual effect, populations can regrow or recolonize in the same field. If the first colonization occurs early in the susceptible stage, two or more treatments may be needed. On a calendar basis, soybean susceptibility can be described as highest during July and into August with potential but lower impacts into September. Aphid colonization may occur as early as late June or as late as late August and even September; however, since it is a relatively new pest in the U.S., entomologists do not have a strong understanding of soybean aphid biology. Building on the early work by Hueth and Regev (1974) and Hall and Norgaard (1973) and incorporating concepts from recent unpublished AAEA selected papers, the treatment decision model is developed (with uncertainty incorporated) and the impacts and treatment options analyzed. The impact of the soybean aphid on yield is described as a function of plant growth stage and cumulative aphid days (CAD) with CAD described as a function of the date of colonization, growth rate, and insecticide application(s) and efficacy. The aphid growth rate is a function of temperature. These functions are estimated using economic and entomological data. Using an example from Minnesota, the preliminary model estimated the value of using a threshold of 100 aphids per plant was estimated to have a treatment value of $41.57 per acre with colonization occurring in mid-July during the growth stage with the highest yield susceptibility, weather conditions were such that the aphid population was doubling every 3 days, and the lag between decision and treatment application was 7 days. Under the same conditions, a threshold of 250 aphids per plant was estimated to have a treatment value of$39.80 per acre. A threshold of 500 aphids was estimated to have a treatment value of $37.88. If colonization occurred earlier in the susceptible stage, say, July 1, the number of treatments increases to two per season and the value of those treatments increases. Using the same conditions as above except for an earlier colonization date and allowing for a second treatment, the value of two treatments with a threshold of 100 aphids per plant was estimated to be$71.02 per acre. With a threshold of 250 aphids, the value of the two treatments was estimated to be $59.77 per acre. For a threshold of 500, the value was estimated to be$41.54 per acre. Other results show the impact of changing parameters and coefficients. These preliminary results indicate that the current economic threshold of 250 aphids per plant accepted by many but not all entomologists may be too high. Earlier and more frequent treatments may be needed when aphids colonize earlier and enjoy good reproductive weather. Late season colonization may not need to be treated except with fast growth conditions. This model for the treatment of soybean aphids can be adjusted to help understand the treatment decision for soybean rust. With soybean rust, growers also face the uncertainty in the occurrence and severity infestation and in the magnitude of the resulting impact if infestation does occur. Rust may spread faster than soybean aphid, so growers may need more remote warning systems. However, the basic model of the impact of the soybean aphid will improve our understanding of the soybean rust problem

The Sophistication and Diversification of the African Agricultural Sector: A Product Space Approach

We use the concept of the product space to analyze the key features of the transformation process in Africa with a focus on the agricultural sector. Between 1962 and 2008, we find that both specialization and diversification occur for the overall economy and across sectors. Our findings also confirm that the transformation of the African economy is driven primarily by the increasing specialization of nonagricultural exports. However, the transformation process is still moving more slowly than that of an emerging economy such as Brazil. The index of specialization of agricultural exports grew at a modest annual rate of 2.1 percent between 1962 and 2008, compared to 5.0 percent for nonagricultural exports and 4.1 percent for the overall economy. Although substantive achievements are observed in terms of product specialization or sophistication, the diversification of agricultural exports is rather insignificant. Compared to Africa, Brazil appears to have experienced a more balanced process in terms of both specialization and diversification of its agriculture. African countries’ specific transformation dynamics are heterogeneous, suggesting that a one-size-fits-all strategy to boost the agricultural sector in Africa is probably not the best option. Therefore, we advocate that the goals and principles of the Comprehensive Africa Agriculture Development Programme (CAADP) be adapted and customized to individual countries and incorporated into their strategies to enhance the transformation process of the African agricultural sector

Assessment of the Capacity, Incentives, and Performance of Agricultural Extension Agents in Western Democratic Republic of Congo

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