Batu Town and Malang Regency which is one of local litchi center centers in East Java. We can see from the end of maret until now the litchi plants in the city of Batu began to blossom the flowers. Flowering events of this litchi usually occur in late maret to mid-November.
Longan crops may flower because they are induced by environmental factors, where such factors for upland areas such as in Batu city are temperature. The intended temperature is a low temperature that occurs for more than 2 months. This happens usually at the end of maret to april in Stone Town and its surroundings.
Figure 1. The longan flowering plants in one corner of Batu city
Flowers that bloom will be meaningless if fertilization does not occur. There are several factors that cause the fruit that will be bushy, including:
- Percentage of the number of female flowers
Litchi flowers have three types: male, female and hermaphrodite flowers. All varieties of litchi have male and female flowers, but hermaphrodite flowers are not necessarily. The hermaphrodite flower is a flower that has a pistil and a flower in one flower, but it actually serves only as a male and if its fruiting twine will fall off. Therefore the number of female flowers affect the fruit so much, the more female flowers will be more and more fruit so vice versa.
- Population of pollinating insects
Pollination of litchi flowers is aided by wind and pollinating insects ie honey bees. Bees that help is the type Apis mellifera. Honey produced is a honey that is easy to meet in the market. Based on the results of research in China, the presence of honeybees can increase the production of longan fruit.
Figure 2. Honey bees that help pollinate longan flowers
- Pest attacks
When the flowers bloom there are some pests that attack, including thrips and aphids. The secretory liquid from the pest is about flowers and leaves that cause dust to stick or so-called dew soot. This soot dust causes the flowers to bloom so much that pollination does not occur. To overcome this can be done insecticidal spraying at the time thrips or aphids attack.
Figure 3. Leaves and flowers are attacked by sooty dew
Other pests that attack when flowering is a caterpillar larvae. This pest strikes at the end of the flower that causes the flowers to dry.
Figure 4. Pests borer attacking litchi flowers
- Water availability
The generative phase of longan plants requires more water than vegetative. Lack of water at the time of flowering will cause dried flowers. Therefore it is necessary to do a routine irrigation at the time of flowering.
Figure 5. The flower tips dry out due to lack of water
- Environmental factors
Environmental factors that affect the pollination event are sunlight, rainfall and wind speed. Sunlight is required for the bag of benangsaries to open. While rainfall and high wind speeds can cause more flowers to fall out.
These factors need to be taken care of so that the flowering season of this year's litchy plants can produce dense fruits. Longan flowering plants in these months can be harvested at the end of maret until the end of April 2018.