P. hysterophorus is an erect, much-branched with vigorous growth habit, aromatic, annual (or a short-lived perennial), herbaceous plant with a deep taproot. The species reproduces by seed. In its neotropical range it grows to 30-90 cm in height (Lorenzi, 1982, Kissmann and Groth, 1992), but up to 1.5 m, or even 2.5 m, in exotic situations (Haseler, 1976, Navie et al., 1996). Shortly after germination the young plant forms a basal rosette of pale green, pubescent, strongly dissected, deeply lobed leaves, 8-20 cm in length and 4-8 cm in width. The rosette stage may persist for considerable periods during unfavourable conditions (such as water or cold stress). As the stem elongates, smaller, narrower and less dissected leaves are produced alternately on the pubescent, rigid, angular, longitudinally-grooved stem, which becomes woody with age. Both leaves and stems are covered with short, soft trichomes, of which four types have been recognized and are considered to be of taxonomic importance within the genus (Kohli and Rani, 1994).;Flower heads are both terminal and axillary, pedunculate and slightly hairy, being composed of many florets formed into small white capitula, 3-5 mm in diameter. Each head consists of five fertile ray florets (sometimes six, seven or eight) and about 40 male disc florets. The first capitulum forms in the terminal leaf axil, with subsequent capitula occurring progressively down the stem on lateral branches arising from the axils of the lower leaves. Thousands of inflorescences, forming in branched clusters, may be produced at the apex of the plant during the season. Seeds (achenes) are black, flattened, about 2 mm long, each with two thin, straw-coloured, spathulate appendages (sterile florets) at the apex which act as air sacs and aid dispersal.
FACTSHEETS FOR FARMERS www.plantwise.org Created in Grenada , October 2012 Aphid control in cabbage Recognize the problem Cabbage aphids look like small lice on plants. They can reduce cabbage farmers' income by decreasing the quality and damaging up to 90% of their crop. Background Aphids are sucking insects that suck the juices from the leaves and tender shoots of plants. They can change the shape of the leaves causing the leaf to curl and can also spread diseases from plant to plant. There are different types of aphids but the usual type...
FACTSHEETS FOR FARMERS www.plantwise.org Created in Trinidad and Tobago , November 2011 Gummy stem blight of watermelon Recognize the problem Gummy stem blight is a major disease of watermelon. This disease often causes total crop loss. It is caused by a fungus. The leaves, stem and fruit may become infected. Brown leaf spots often start close to the edge of the leaves. The spots become larger, irregular and may join together and kill the leaf. Older leaves at the base of the plant turn yellow, become dry and fall off. The stem may split at the...
FACTSHEETS FOR FARMERS www.plantwise.org Created in Trinidad and Tobago , November 2011 Angular leaf spot in cucumber Recognize the problem Angular leaf spot is a common disease of cucumber, squash, pumpkin and watermelon. Affected plants bear less and the fruits are smaller. This disease causes water-soaked spots on leaves, stems and fruits. Leaf spots are not round but spread out to the leaf veins, so they look angular, or pointed. The spots on top of the leaves are grey to light brown, but spots under the leaves are usually shiny or gummy. The...
The REAL pocket-sized monster The fall ar mywor m is a new pest at tacking maize in Af r ica. The eggs and cater pillar are easiest to spot on the leaves and growing point of your maize. You can tell when a cater pillar is a fall ar mywor m by the 4 dots on its second to last segment and the upside down Y on its he\ ad. Its lifecycle includes eggs which hatch into cater pillars that grow to become pupae, f rom which a moth emerges. Each and every stage is bad for your maize. See it. Squash it. Stop it. Pupa Moth Eggs Caterpillar F a ll a rmyworm
Gummy Stem Blight of Greenhouse Cucumber March, 2018 Gummy stem blight (GSB) is caused by the fungus Didymella bryoniae, previously known as Mycosphaerella melonis. The fungus is known to infect cucurbits, including cucumber, pumpkin, squash, watermelon, cantaloupe and many others. Under favourable climatic conditions, the pathogen can infect all parts, except roots, of the cucumber plant at all stages of plant development. Infection at fruit development often leads to internal fruit rot that may go unnoticed at harvest. This raises concern among growers because the...
Photo 1 . Lep to glo ssu s n ym phs f e ed in g o n w ild cu cu rb it . Photo 2 . L eaf-fo ote d b ug, Lep to glo ssu s s p ecie s, on s n ake g o urd . Photo 3 . L eaf-fo ote d b ug, Lep to glo ssu s s p ecie s, on t o m ato c le arly s h ow in g t h e " le af" o f t h e le g. Photo 4 . L eaf-fo ote d b ug, Lep to glo ssu s s p ecie s, on lu ffa . Photo 5 . L eaf-fo ote d b ug, Lep to glo ssu s s p ecie s, on f lo w er o f p um pkin w it h " le af" o f t h e le g cle arly s h ow in g. P acif ic P ests a n d P ath ogen s - F a ct S h eets P acif ic...
LOSE LESS, FEED MORE Plantwise is a CABI -led global initiative. www.plantwise.org PEST MANAGEMENT DECISION GUIDE: GREEN AND YELLOW LIST Fall Armyworm. Spodoptera frugiperda Damage on the funnel by larvae (Photo: M. Kasina, KALRO, Kenya Y” pattern on head of Armyworm larva (Photo: desiree vanheerden Syngenta) Prevention Monitoring Direct Control Direct Control Restrictions Plough deep to expose the pupae to predators and solar heat Avoid late or off -season planting , plant early to avoid pest population build up...
Watermelon plants produce separate male flowers, which make pollen, and female flowers which bear fruits. In order to set marketable fruit, bees need to transfer 500-1,000 pollen grains from male flowers to female flowers. Therefore, it’s important to consider pollination strategies that ensure consistent and reliable fruit set. Honey bees are the most important pollinators of commercial watermelon in California. However, some fields also receive pollination from wild bees like bumble bees and sweat bees. Like honey bees, these pollinators visit watermelon flowers to collect pollen and...
Pumpkins require cross-pollination. Bees are needed to move pollen from the plant’s male flowers to the female flowers. Individual flowers have a short pollination window; flowers are typically only open from dawn until noon. Therefore, it’s important to consider pollination strategies that ensure consistent fruit set. Managed honey bees are brought in for pollination, but in many fields, wild bees such as bumble bees and squash bees are the most common pollinators. Like honey bees, these pollinators visit pumpkin flowers to collect pollen and nectar. Pumpkins Require Pollination...
Pumpkins need bees to move pollen from male flowers to female flowers to set fruit. Individual flowers have a short pollination window; flowers are typically only open from dawn until noon. Therefore, it’s important to consider pollination strategies that ensure consistent fruit set. Managed honey bees are brought in for pollination, but in many fields, wild bees such as bumble bees and squash bees are the most common pollinators. Like honey bees, these pollinators visit pumpkin flowers to collect pollen and nectar. Pumpkins Require Pollination Integrated Crop Pollination:...
1 Pest description and damage The western spotted cucumber beetle (Diabrotica undecimpunctata), commonly called the “12-spot beetle,” is an insect pest of snap beans, corn, squash, cucumbers, and other vegetable crops in the Willamette Valley. Adult 12-spot beetles: • Are yellowish green, ¼ inch long, and have 12 black spots on their wing covers (Figure 1). • Eat and damage leaves and pods of snap beans. Feeding beetles scar and deform the beans. 12-spot beetle larvae (known as southern corn root worms): • Are wormlike and white, except for the head and last abdominal...
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P. hysterophorus is known to reduce the yield of various crops and to compete with pasture species in various countries. However, the yield loss and specific effects on the crops have not been quantified in all countries (Rubaba et al., 2017).;In Australia, the main impact of P. hysterophorus has been in the pastoral region of Queensland, where it replaces forage plants, thereby reducing the carrying capacity for grazing animals (Haseler, 1976, Chippendale and Panetta, 1994). Serious encroachment and replacement of pasture grasses has also been reported in India (Jayachandra, 1971) and in Ethiopia (Tamado, 2001, Taye, 2002). The weed is also able to invade natural ecosystems, and has caused total habitat changes in native Australian grasslands and open woodlands (McFadyen, 1992).;In India, the yield losses are reported as up to 40% in several crops and a 90% reduction of forage production (Gnanavel, 2013). P. hysterophorus is now being reported from India as a serious problem in cotton, groundnuts, potatoes and sorghum, as well as in more traditional crops such as okra (Abelmoschus esculentus), brinjal (Solanum melongena), chickpea and sesame (Kohli and Rani, 1994), and is also proving to be problematic in a range of orchard crops, including vineyards, olives, cashew, coconut, guava, mango and papaya (Tripathi et al., 1991, Mahadevappa, 1997, Gnanavel, 2013).;Similar infestations of sugarcane and sunflower plantations have recently been noted in Australia (Parsons and Cuthbertson, 1992, Navie et al., 1996), whilst in Brazil and Kenya, the principal crop affected is coffee (Njoroge, 1989, Kissmann and Groth, 1992). In Ethiopia, parthenium weed was observed to grow in maize, sorghum, cotton, finger millet (Eleusine coracana), haricot bean (Phaseolus vulgaris), tef (Eragrostis tef), vegetables (potato, tomato, onion, carrot) and fruit orchards (citrus, mango, papaya and banana) (Taye, 2002). In Pakistan, the weed has been reported from number of crops, including wheat, rice, sugarcane, sorghum, maize, squash, gourd and water melon (Shabbir 2006, Shabbir et al. 2011, Anwar et al. 2012).;In Mexico, the species is reported as a weed in cotton, rice, sugarcane, Citrus spp, beans, safflower, sunflower, lentils, corn, mango, okra, bananas, tomato, grapes, alfalfa, chili peppers, luffa, marigolds and other vegetables and fruit orchards. It is also a weed in nurseries. In Argentina is reported as a weed of tobacco fields (CONABIO, 2018).;Gnanavel (2013) also reports the following detrimental effects of P. hysterophorus on crops: it inhibits nitrogen fixing bacteria in legumes, the vast quantity of pollen it produces (ca. 624 million/plants) inhibits fruit setting, it is an alternative host for viruses that cause diseases in crop plants, and it is an alternative host for mealy bugs.